Stuffing unit with combined vibration generation

Description

[0001] The invention relates to a tamping unit for tamping under the sleepers of a track, comprising tamping tools arranged in pairs with tamping picks mounted in holders, wherein each tamping tool is assigned a hydraulic actuator for generating an assisting movement of the tamping picks and wherein an eccentric drive for generating a vibration movement of the tamping picks is arranged such that each of the hydraulic actuators is connected on one side to the eccentric drive and on the other side to the upper end of the pivot lever of the assigned tamping tool.

[0002] To create and maintain the correct track alignment of a railway track, vertically movable tamping units are used, among other things, which are arranged with other units on track construction machines.

[0003] Tamping picks, arranged in pairs perpendicular to the rail, are positioned above a sleeper of the track grid and then lowered vertically until they penetrate the ballast layer of the track superstructure. The pairs of tamping picks are then aligned by means of forces applied by hydraulic actuators and transmitted via pivoting levers. The ballast located between the pairs of tamping picks and below the sleeper (which has been raised along with the surrounding track grid by a lifting and aligning unit) is redistributed and compacted, thus correcting a faulty track position from a measured initial position to a predetermined target position.

[0004] According to the state of the art, the positioning movement of the tamping picks is superimposed with a vibration movement, which on the one hand facilitates the immersion of the tamping picks into the gravel and on the other hand promotes effective movement of the tamping picks in the gravel.

[0005] According to the state of the art, such oscillatory movements are generated on the one hand by eccentric shafts and transmitted to the tamping picks by means of the hydraulic actuators and the pivot lever of the tamping unit, or on the other hand by a suitable time-varying supply and discharge of the hydraulic medium into the pressure chambers of the hydraulic actuator, in order to then also act on the tamping picks by means of the pivot lever.

[0006] While vibration generation with an eccentric shaft achieves a predetermined vibration amplitude even with a hard gravel layer and can be operated more energy-efficiently compared to a hydraulic actuator, in this first embodiment switching on and off processes take longer and can consequently lead to noise emissions and wear even between tamping cycles.

[0007] In vibration generation with hydraulic actuators, the possibility of more dynamic use and more flexible application of this alternative embodiment due to shorter switching times is offset by a lower efficiency and a limited choice of vibration frequency and amplitude due to the characteristics of the switching valves that control the flow of the hydraulic medium into and out of the pressure chambers of the actuators.

[0008] AT 519 219 A4 discloses a tamping unit for tamping under sleepers of a track, comprising opposing tamping tools, each of which is connected to an assisting cylinder for generating an assisting movement and to an eccentric drive for generating a vibration movement.

[0009] One of the auxiliary cylinders, arranged in pairs, is mechanically connected to the eccentric drive, and the pressure changes generated in the pressure chambers of this auxiliary cylinder by the eccentric drive are hydraulically transmitted via a connecting line between a first pressure chamber of the auxiliary cylinder connected to the eccentric drive and a second pressure chamber of the other auxiliary cylinder.

[0010] The invention is based on the objective of providing an improvement over the prior art for a tamping unit of the type mentioned above with regard to the generation of vibrations for the tamping picks acting in the ballast layer of the railway track superstructure. A further objective of the invention is to describe a method for operating the improved tamping unit.

[0011] According to the invention, this problem is solved by a stuffing unit according to claim 1 and a method for operating the stuffing unit according to claim 7.

[0012] Dependent claims specify advantageous embodiments of the invention.

[0013] The tamping unit according to the invention for tamping under the sleepers of a track comprises tamping tools arranged in pairs relative to each other, with tamping picks fixed in holders, wherein each tamping tool is assigned a hydraulic actuator for generating an adjustment movement of the tamping picks, and wherein an eccentric drive for generating a first vibration movement of the tamping picks is arranged such that each of the hydraulic actuators is connected on one side to the eccentric drive and on the other side to an upper end of a pivot lever of the assigned tamping tool, and wherein a hydraulic switching element is arranged between pressure chamber connections of the respective hydraulic actuator and a hydraulic line network, wherein the respective hydraulic switching element is configured to generate a second vibration movement in the assigned hydraulic actuator, and wherein the respective pivot lever is configured toto transfer a superposition of the first and second vibration movements to the respective tamping pick.

[0014] This embodiment according to the invention of a combined vibration generation using an eccentric shaft and hydraulic actuators is particularly suitable for retrofitting existing tamping units.

[0015] The stuffing unit according to the invention can also be operated more energy-efficiently than those units known from the prior art which generate the vibrations exclusively by means of hydraulic actuators.

[0016] The combination of two different designs for generating vibrations also increases the reliability of the entire stuffing unit.

[0017] In particular, the tamping unit according to the invention can maintain a vibration amplitude generated by the eccentric shaft at the tamping pick, even if the configuration of the gravel layer prevents the generation and transmission of vibrations generated by hydraulic actuators.

[0018] In a preferred embodiment of the invention, the respective hydraulic switching element has four connections, two of which are connected to pressure chamber connections of the hydraulic actuator associated with it and two others to the hydraulic piping network.

[0019] Preferably, the respective hydraulic switching element is characterized by three switching positions, wherein in the first middle passive switching position the pressure chamber connections of the associated hydraulic actuator are disconnected from the hydraulic line network, wherein in a second active switching position a first line network connection is fluidly connected to the pressure chamber connection of the piston-side pressure chamber and a second line network connection is fluidly connected to the pressure chamber connection of the rod-side pressure chamber, and wherein in a third active switching position the first line network connection is fluidly connected to the rod-side pressure chamber and the second line network connection is fluidly connected to the piston-side pressure chamber.

[0020] It is advantageous if, for maintaining the middle passive switching position, two mechanical springs are provided on each of the two sides of the respective hydraulic switching element, and for changing from this middle passive switching position to one of the two active switching positions, an electromagnetic actuator is provided on each of the two sides of the hydraulic switching element, which acts against the mechanical force of the respective opposite spring.

[0021] In a preferred further development, a control device is provided for controlling the respective hydraulic switching element.

[0022] It is advantageous if a measuring device is arranged to detect the piston position of the respective hydraulic actuator and / or the angular position of the associated pivot lever and / or the position of the associated tamping pick.

[0023] The method for operating a stuffing unit according to the invention executes a control program for controlling at least one hydraulic switching element.

[0024] Preferably, this control program is stored and executed on the control device.

[0025] In a preferred embodiment, measured values ​​from a measuring device for detecting the piston position of the respective hydraulic actuator and / or the angular position of the associated pivot lever and / or the position of the associated tamping pick are evaluated within the control program.

[0026] In an advantageous further development, in addition to the aforementioned measured values, the angular position of the eccentric shaft is also recorded and evaluated by the control program in order to enable active control of the swivel lever and tamping pick in the case where the total amplitude at the pivot lever and the tamping pick is compensated to zero by two equally large, antiphase oscillations of the eccentric drive and the hydraulic actuator.

[0027] In an advantageous operating state of the method, the control program of the control device and, if applicable, the measured values ​​of the measuring device generate a second vibration oscillation with the same frequency and phase angle relative to the first vibration oscillation with a defined frequency, in addition to the first vibration oscillation generated by means of the eccentric drive, by suitable control of the respective hydraulic switch in the associated hydraulic actuator.

[0028] Through such a constructive superposition of the two vibrations, it is possible to dynamically adapt the resulting vibration amplitude of the tamping picks to the given state of the gravel layer being worked.

[0029] In another favorable alternative operating state of the method, the control program of the control device and, if necessary, the measured values ​​of the measuring device generate a second vibration oscillation with the same frequency and an exactly opposite phase to the first vibration oscillation, in addition to the first vibration oscillation with a defined frequency generated by means of the eccentric drive, due to suitable control of the respective hydraulic switch in the associated hydraulic actuator.

[0030] With this compensating superposition of the two vibrations, it is possible to reduce or even avoid the noise emission and wear of the packing unit according to the invention between the packing cycles.

[0031] The invention is explained below by way of example with reference to the accompanying figures. These show, in schematic representation: Fig. 1 A tamping unit partially lowered relative to a track. Fig. 2 A tamping unit lowered into the ballast layer of a railway track with measuring and control device. Fig. 3 The control of a hydraulic actuator by means of an embodiment of the hydraulic switching element. Fig. 4 A track construction machine with a tamping unit and a lifting and aligning unit. Fig. 5 An embodiment of three tamping units in a common unit frame for the synchronous tamping of up to three sleepers.

[0032] In Figure 1A tamping unit 1 is shown, comprising tamping tools 4a, 4b arranged in pairs and movable vertically relative to the plane of a rail track. These tools include tamping picks 5a, 5b and rotatably mounted pivot levers 8a, 8b. The piston rods of linearly acting hydraulic actuators 6a, 6b act on the sides of the pivot levers 8a, 8b opposite the tamping picks 5a, 5b. The cylinders of these hydraulic actuators are connected to an eccentric shaft 7, which is designed to transmit a vibration with a defined amplitude via the hydraulic actuators 6a, 6b and the pivot levers 8a, 8b to the tamping picks 5a, 5b. The schematic section of track 3 shows that the tamping unit 1 is half lowered between a raised starting position without contact of the tamping picks 5a, 5b with the ballast layer 20 and a fully lowered end position in which the tamping picks 5a, 5b are completely in the ballast layer 20.

[0033] Figure 2 The stuffing unit 1 is shown. Figure 1 in such a fully lowered final position. On the ballast layer 20, which is also referred to as ballast bed, rests the track grid of a railway track, in which rails 3 of a track are fastened by sleepers 2 arranged at equal intervals transversely to the rails 3.

[0034] Besides the in Figure 1 The vibration excitation shown by the rotating eccentric shaft 7, which is transmitted to the tamping picks, is further excited by the hydraulic switching elements 9a, 9b assigned to the respective hydraulic actuators 6a, 6b, which are connected to a hydraulic line network 10, by suitable control via a control device 15, in the pressure chambers 12a, 12b of the hydraulic actuators 6, 6a, 6b, which are transmitted via the pivot levers 8a, 8b of the tamping tools 4a, 4b to the tamping picks 5a, 5b.

[0035] Measured values ​​of the position of the piston in the housing of the respective hydraulic actuator 6, 6a, 6b, the angular position of the respective pivot lever 8a, 8b and the position of the respective tamping pick 5a, 5b of the respective tamping tools 4a, 4b, recorded by measuring sensors 16a, 16b and 16c, are transmitted to the control device 15 via a measuring device 16.

[0036] In a control program 17, which is installed and executed on the control device 15, these measured values ​​recorded by means of the sensors 16a, 16b, 16c can be evaluated in order to determine suitable control signals for the switching elements 9a, 9b.

[0037] Sensors 16a, 16b, 16c are in Figure 2For the sake of clarity, only the side of the tamping tool 4b is shown. In a further embodiment, however, they can be arranged for both the components of the tamping tool 4b and those of the tamping tool 4a in order to enable independent control of the two tamping tools 4a, 4b by the control device 15 and the control program 17 executed on it, taking into account the respective current measured values ​​of the state variables piston position, pivot lever angle position and tamping pick position of the tamping tools 4a, 4b.

[0038] An example of controlling a hydraulic actuator 6 using a hydraulic switching element 9 is shown in Figure 3A hydraulic 4 / 3 proportional valve, as an embodiment of the hydraulic switching element 9, is arranged between the pressure chamber connections 11a, 11b of the pressure chambers 12a, 12b of the hydraulic actuator 6 and the two connections P and T of the hydraulic line network 10, which includes pressure sources, hydraulic lines and pressure sinks, in order to control the supply and discharge of the hydraulic medium into and from the pressure chambers 12a, 12b of the hydraulic actuator 6 and thus to influence the piston position and its change over time in the hydraulic actuator 6.

[0039] In a passive neutral position of the hydraulic actuator 9, the pressure chamber connections 11a, 11b are disconnected from the connecting lines P, T of the hydraulic line network 10 and the piston position is not changed.

[0040] This passive center position is fixed by mechanical springs 13a, 13b on both sides of the proportional slide valve 9.

[0041] A first active position of the hydraulic switching element 9 connects the hydraulic line network connection P with the pressure chamber connection 11a of the piston-side pressure chamber 12a of the hydraulic actuator 6, whereby the hydraulic medium can flow from the line network 10 to the hydraulic actuator 6, and the pressure chamber connection 11b of the rod-side pressure chamber 12b of the hydraulic actuator 6 with the hydraulic line network connection T, whereby the hydraulic medium can flow from the hydraulic actuator 6 to the line network 10.

[0042] The hydraulic switching element 9 is continuously moved from the passive starting position to this first active position by activating an electromagnetic actuator 14b and acting against the spring force of the mechanical spring 13a.

[0043] The second active position of the hydraulic switching element 9 connects the hydraulic line network connection P with the pressure chamber connection 11b of the rod-side pressure chamber 12b of the hydraulic actuator 6, whereby the hydraulic medium can flow from the line network 10 to the hydraulic actuator 6, and the pressure chamber connection 11a of the piston-side pressure chamber 12a of the hydraulic actuator 6 with the hydraulic line network connection T, whereby the hydraulic medium can flow from the hydraulic actuator 6 to the line network 10.

[0044] The hydraulic switching element 9 is continuously moved from the passive starting position to this second active position by activating an electromagnetic actuator 14a and acting against the spring force of the mechanical spring 13b.

[0045] A rail vehicle equipped as a track construction machine 18 is in Figure 4depicted on a railway track, of which the track grid, consisting of track 3 and sleepers 2, is shown, resting on a layer of ballast 20.

[0046] This track construction machine 18 carries, in addition to the tamping unit 1, a lifting and aligning unit 19 arranged in the working direction in front of the tamping unit 1, which lifts the track grid 2, 3 to enable the tamping of the sleepers 2 by means of the tamping unit 1.

[0047] Figure 5 shows a difference from the stuffing unit. Figures 1 and 2 A different embodiment with which up to three thresholds can be tamped simultaneously.

[0048] In this embodiment, three tamping units 1 are arranged in a common unit frame 21. The tamping units 1 can be lowered independently of each other.

[0049] Each tamping unit has its own eccentric shaft 7, with which the vibrations generated by it can be transmitted via the hydraulic actuators 6c, 6d, 6e, 6f, 6g, 6h and the pivot levers 8c, 8d, 8e, 8f, 8g, 8h to the tamping picks 5c, 5d, 5e, 5f, 5g, 5h.

[0050] In order to achieve a compact design of the entire assembly 21, the two outer stuffing units 1 are designed asymmetrically compared to the inner stuffing unit 1 with regard to the length and position of the hydraulic actuators 6c, 6d, 6e, 6f, 6g, 6h as well as the length and bearing of the pivot levers 8c, 8d, 8e, 8f, 8g, 8h.

[0051] By constructively or compensating the superposition of vibrations additionally generated by the hydraulic actuators 6c, 6d, 6e, 6f, 6g, 6h with the vibrations generated by the eccentric shafts 7, the vibration movements of each individual tamping pick 5c, 5d, 5e, 5f, 5g, 5h can also be appropriately selected in this embodiment based on the requirements of the tamping process and the condition of the gravel layer 20.

[0052] The subject matter of the invention is not limited to the embodiments shown in the figures. In particular, further embodiments and arrangements of hydraulic control elements 9, such as two 3 / 2-way valves or four 2 / 2-way valves per hydraulic actuator 6, as well as other embodiments of the tamping units 2 for the simultaneous tamping of more than one threshold 2, are also included by the claims.

Claims

1. A tamping unit (1) for tamping sleepers (2) of a track (3) comprising tamping tools (4a, 4b) aligned towards each other in pairs with tamping tines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) fixed in holders, with a hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) for generating a squeezing movement of the tamping tines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) being assigned to each tamping tool (4a, 4b), and with an eccentric drive (7) for generating a first vibrational movement of the tamping tines (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) being arranged in such a way that one of the hydraulic actuators (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) is connected on the one hand to the eccentric drive (7) and, on the other hand, to an upper end of a tilting lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) of the assigned tamping tool (4a, 4b), characterized in that one hydraulic switching element (9, 9a, 9b) is arranged between pressure chamber connectors (11a, 11b) of the respective hydraulic actuator (6, 6a, 6b) and a hydraulic line network (10), that the respective hydraulic switching element (9, 9a, 9b) is set up to generate a second vibrational movement in the assigned hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h), and that the respective tilting lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) is set up to transmit a superposition of the first and the second vibrational movement to the respective tamping tine (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h).

2. A tamping unit (1) according to claim 1, characterized in that the respective hydraulic switching element (9, 9a, 9b) has four connectors, two of which are connected to pressure chamber connectors (11a, 11b) of the hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) assigned thereto and two others are connected to the hydraulic line network (10).

3. A tamping unit (1) according to claim 2, characterized in that the respective hydraulic switching element (9, 9a, 9b) has three switching positions, with the pressure chamber connectors (11a, 11b) of the assigned hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) being disconnected from the hydraulic line network (10) in the first central passive switching position, with a first line network connector (P) being fluidly connected to the pressure chamber connector (11a) of the piston-side pressure chamber (12a) and a second line network connector (T) being fluidly connected to the pressure chamber connector (11b) of the rod-side pressure chamber (12b) in a second active switching position, and with the first line network connector (P) being fluidly connected to the rod-side pressure chamber (12a) and the second line network connector (T) being fluidly connected to the piston-side pressure chamber (12b) in a third active switching position.

4. A tamping unit (1) according to claim 3, characterized in that two mechanical springs (13a, 13b) are provided on one of the two sides of the respective hydraulic switching element (9, 9a, 9b) to maintain the central passive switching position, and one electromagnetic actuator (14a, 14b) is provided on one of the two sides of the hydraulic switching element (9, 9a, 9b), which acts against the mechanical force of the opposite spring (13a, 13b), to change from this central passive switching position to one of the two active switching positions.

5. A tamping unit (1) according to the claims 1 to 4, characterized in that a control device (15) is provided for actuating the respective hydraulic switching element (9, 9a, 9b).

6. A tamping unit (1) according to the claims 1 to 5, characterized in that a measuring device (16) is arranged for recording the piston position (16a) of the respective hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h), and / or the angular position (16c) of the assigned tilting lever, and / or the position (16b) of the assigned tamping tine.

7. A method for operating a tamping unit (1) according to one of the claims 1 to 6, characterized in that a control program (17) is executed, preferably on a control device (15), for actuating at least one hydraulic switching element (9, 9a, 9b).

8. A method according to claim 7, characterized in that measured values of a measuring device (16) for recording the piston position (16a) of the respective hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h), and / or the angular position (16c) of the assigned tilting lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h), and / or the position (16b) of the assigned tamping tine (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) are evaluated within the control program (17).

9. A method according to claim 7 or 8, characterized in that a second vibration oscillation with the same frequency and, in relation to the first vibration oscillation, the same phase position is generated in the assigned hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) by the control program (17) of the control device (15) and, as the case may be, based on the measured values of the measuring device (16, 16a, 16b, 16c), in addition to the first vibration oscillation, generated by the eccentric drive (7) with a defined frequency, due to suitable actuation of the respective hydraulic switch (9, 9a, 9b).

10. A method for operating a tamping unit (1) according to claim 7 or 8, characterized in that a second vibration oscillation with the same frequency and, in relation to the first vibration oscillation, the exactly opposite phase position is generated in the assigned hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) by the control program (17) of the control device (15) and, as the case may be, based on the measured values of the measuring device (16, 16a, 16b, 16c), in addition to the first vibration oscillation, generated by the eccentric drive (7) with a defined frequency, due to suitable actuation of the respective hydraulic switch (9, 9a, 9b).