Tamping unit with combined generation of vibrations

Abstract

The invention relates to a tamping unit (1) for tamping sleepers (2) of a track (3), comprising tamping tools (4a, 4b) aligned in pairs with tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) fastened in holders, wherein each tamping tool (4a, 4b) is assigned a hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) for generating an adjusting movement of the tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h), and wherein an eccentric drive (7) for generating a first vibration movement of the tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) is arranged in such a way is 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 pivot lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) of the associated tamping tool (4a, 4b), and wherein a hydraulic switching element (9, 9a, 9b) is connected between pressure chamber connections (11a,11b) of the respective hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) and a hydraulic line network (10), wherein the respective hydraulic switching element (9, 9a, 9b) is configured to generate a second vibration movement in the associated hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h), and wherein the respective pivot lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) is configured to transmit a superposition of the first and second vibration movements to the respective tamping pick (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h).

Description

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

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

[0003] Tamping tines arranged in pairs across the track are positioned above a sleeper in the track grid and then lowered vertically until they penetrate the ballast layer of the track superstructure. The tamping tine pairs are then moved toward each other by forces applied by hydraulic actuators and transmitted by pivoting levers. The ballast located between the tamping tine pairs and below the sleeper, which is raised by a lifting and straightening unit with the surrounding track grid, is relocated and compacted, thus bringing a faulty track position from a measured initial position to a specified target position.

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

[0005] According to the state of the art, such oscillating movements are generated on the one hand by eccentric shafts and transmitted to the tamping tines by means of the hydraulic actuators and the pivoting levers 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 then to act on the tamping tines by means of the pivoting lever.

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

[0007] When generating vibrations with hydraulic actuators, the possibility of more dynamic use and more flexible application of this alternative embodiment due to shorter switching on and off 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 inflow and outflow of the hydraulic medium into and from the pressure chambers of the actuators.

[0008] AT 519 219 A4 discloses a tamping unit for tamping sleepers of a track, comprising opposing tamping tools, each of which is connected to an adjusting cylinder for generating an adjusting movement and an eccentric drive for generating a vibrating 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 transmitted hydraulically 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 object of providing an improvement over the prior art for a tamping unit of the type mentioned above with regard to the vibration generation for the tamping picks acting in the ballast layer of the railway track superstructure. A further object of the invention is to describe a method for operating the improved tamping unit.

[0011] According to the invention, this object is achieved by a tamping unit according to claim 1 and a method for operating the tamping unit according to claim 7.

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

[0013] The tamping unit according to the invention for tamping sleepers of a track comprises tamping tools aligned in pairs with tamping tines fastened in holders, wherein each tamping tool is assigned a hydraulic actuator for generating an adjusting movement of the tamping tines and wherein an eccentric drive for generating a first vibrating movement of the tamping tines is arranged such that one of the hydraulic actuators is connected on the one hand to the eccentric drive and on the other hand to an upper end of a pivoting lever of the associated 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 designed to generate a second vibrating movement in the associated hydraulic actuator and wherein the respective pivoting lever is designed toto transfer a superposition of the first and second vibration movements to the respective tamping pick.,

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

[0015] The tamping 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 vibration also increases the reliability of the entire tamping unit.

[0017] By means of the tamping unit according to the invention, in particular a vibration amplitude generated by the eccentric shaft can be maintained at the tamping pick, even if the configuration of the ballast layer prevents the generation and transmission of vibrations generated by hydraulic actuators.

[0018] In a preferred development of the subject matter of the invention, the respective hydraulic switching element has four connections, two of which are connected to pressure chamber connections of the hydraulic actuator assigned thereto and two further ones to the hydraulic line 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 separated 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, to maintain the middle passive switching position, two mechanical springs are provided on each of the two sides of the respective hydraulic switching element and, to change 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 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 tamping 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 ​​of 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 above-mentioned 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 pivot lever and tamping tine in the case in which the total amplitude at the pivot lever and the tamping tine is compensated to zero by two equal, antiphase oscillations of the eccentric drive and the hydraulic actuator.

[0027] In an advantageous functional state of the method, a second vibration oscillation with the same frequency and the same phase position compared to the first vibration oscillation is generated by the control program of the control device and, if appropriate, based on the measured values ​​of the measuring device, 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.

[0028] By 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 condition of the ballast layer to be processed.

[0029] In a further advantageous alternative functional state of the method, in addition to the first vibration oscillation with a defined frequency generated by means of the eccentric drive, a second vibration oscillation with the same frequency and exactly opposite phase position to the first vibration oscillation is generated by the control program of the control device and, if applicable, based on the measured values ​​of the measuring device 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 tamping unit according to the invention between the tamping cycles.

[0031] The invention is explained below by way of example with reference to the accompanying figures. They show schematically: Fig. 1A tamping unit half-submerged relative to a track Fig. 2A tamping unit lowered into the ballast layer of a railway track with measuring and control device Fig. 3The control of a hydraulic actuator by means of an embodiment of the hydraulic switching element Fig. 4A track maintenance machine with a tamping unit and a lifting and straightening unit Fig. 5An 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, with tamping tools 4a, 4b arranged in pairs, which can be displaced vertically relative to the plane of a rail track and comprise tamping tines 5a, 5b and rotatably mounted pivot levers 8a, 8b. The piston rods of linearly acting hydraulic actuators 6a, 6b engage the sides of the pivot levers 8a, 8b opposite the tamping tines 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 to the tamping tines 5a, 5b via the hydraulic actuators 6a, 6b and the pivot levers 8a, 8b. The schematic section of a track 3 shows that the tamping unit 1 is half lowered between a raised initial position without contact of the tamping picks 5a, 5b with the ballast layer 20 and a fully lowered final position in which the tamping picks 5a, 5b are completely in the ballast layer 20.

[0033] Figure 2 shows the tamping unit 1 from Figure 1 in such a fully lowered final position. The track grid of a railway track rests on the ballast layer 20, also referred to as ballast bedding. The rails 3 of a track are fastened by sleepers 2 arranged at equal intervals transversely to the rails 3.

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

[0035] Via a measuring device 16, measured values ​​recorded by measuring sensors or sensors 16a, 16b and 16c 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 are transmitted to the control device 15.

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

[0037] The sensors 16a, 16b, 16c are in Figure 2For reasons of clarity, they are shown only for the side of the tamping tool 4b. 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 thereon, taking into account the respective current measured values ​​of the state variables piston position, pivot lever angle position, and tamping tine position of the tamping tools 4a, 4b.

[0038] An exemplary control of a hydraulic actuator 6 by means of a hydraulic switching element 9 is shown in Figure 3shown. A hydraulic 4 / 3 proportional valve is arranged as an embodiment of the hydraulic switching element 9 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 temporal change in the hydraulic actuator 6.

[0039] In a passive middle position of the hydraulic actuating element 9, the pressure chamber connections 11a, 11b are separated 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, as well as 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 initial 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, as well as 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 initial position into 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 4on a railway track, of which the track grid, consisting of track 3 and sleepers 2, is shown, supported on a ballast layer 20.

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

[0047] Figure 5 shows a comparison with the tamping unit from the Figures 1 and 2 Different design with which up to three sleepers can be tamped at the same time.

[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 one another.

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

[0050] In order to achieve a compact design of the entire unit arrangement 21, the two outer tamping units 1 are designed asymmetrically with respect to the inner tamping 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 constructive or compensating 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 suitably selected in this embodiment based on the requirements of the tamping process and the condition of the ballast layer 20.

[0052] The subject matter of the invention is not limited to the embodiments illustrated 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 sleeper 2, are encompassed by the claims.

Claims

1. Tamping unit (1) for tamping sleepers (2) of a track (3), comprising tamping tools (4a, 4b) aligned in pairs with tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) fastened in holders, wherein each tamping tool (4a, 4b) is assigned a hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) for generating an adjusting movement of the tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h), and wherein an eccentric drive (7) for generating a first vibrating movement of the tamping picks (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) is arranged such that that each 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 pivot lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) of the associated tamping tool (4a, 4b), characterized in thata hydraulic switching element (9, 9a, 9b) is arranged between pressure chamber connections (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 designed to generate a second vibration movement in the associated hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h), and that the respective pivot lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) is designed to transmit a superposition of the first and second vibration movements to the respective tamping pick (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h).

2. Tamping unit (1) according to claim 1, characterized in that the respective hydraulic switching element (9, 9a, 9b) has four connections, two of which are connected to pressure chamber connections (11a, 11b) of the hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) assigned to it, and two others are connected to the hydraulic line network (10). ​3. Tamping unit (1) according to claim 2, characterized in that the respective hydraulic switching element (9, 9a, 9b) has three switching positions, wherein in the first middle passive switching position the pressure chamber connections (11a, 11b) of the associated hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h) are separated from the hydraulic line network (10), wherein in a second active switching position a first line network connection (P) is fluidically connected to the pressure chamber connection (11a) of the piston-side pressure chamber (12a) and a second line network connection (T) is fluidically connected to the pressure chamber connection (11b) of the rod-side pressure chamber (12b), and wherein in a third active switching position the first line network connection (P) is fluidically connected to the rod-side pressure chamber (12a) and the second line network connection (T) is fluidically connected to the piston-side pressure chamber (12b) is.

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

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

6. Tamping unit (1) according to claims 1 to 5, characterized in that ​a measuring device (16) for detecting 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 associated pivot lever and / or the position (16b) of the associated tamping pick is arranged.

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

8. Method according to claim 7, ​ Within the control program (17), measured values ​​of a measuring device (16) for detecting 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 associated pivot lever (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) and / or the position (16b) of the associated tamping pick (5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h) are evaluated.

9. Method according to claim 7 or 8, ​ by the control program (17) of the control device (15) and optionally based on the measured values ​​of the measuring device (16, 16a, 16b, 16c), in addition to the first vibration oscillation with a defined frequency generated by means of the eccentric drive (7), a second vibration oscillation with the same frequency and the same phase position as the first vibration oscillation is generated due to suitable control of the respective hydraulic switch (9, 9a, 9b) in the associated hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h).

10. Method for operating a tamping unit (1) according to claim 7 or 8, ​by means of the control program (17) of the control device (15) and optionally on the basis of the measured values ​​of the measuring device (16, 16a, 16b, 16c), in addition to the first vibration oscillation with a defined frequency generated by means of the eccentric drive (7), a second vibration oscillation with the same frequency and exactly the opposite phase position to the first vibration oscillation is generated due to suitable control of the respective hydraulic switch (9, 9a, 9b) in the associated hydraulic actuator (6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h).

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