METHOD FOR OPERATING A tamping unit of a track-laying machine as well as a tamping device for track bed compaction and a track-laying machine

Description

field of technology

[0001] The invention relates to a method for operating a tamping unit of a track construction machine and furthermore to a tamping device for track bed compaction and a track construction machine. State of the art

[0002] Rail-guided track maintenance machines are used to maintain track beds. These machines have a vertically movable tamping unit with a frame and at least two tamping picks that can be moved relative to the frame. During operation, the tamping unit is repeatedly moved vertically between a return position, in which it is disengaged from the track bed, and an engagement position, in which it is engaged with the track bed. In addition, the at least two tamping picks are moved cyclically relative to the frame. This places considerable stress on the tamping unit, which can lead to damage, particularly the breakage of a tamping pick.If the tamping unit is damaged, the track bed will not be compacted sufficiently, and functional components of the tamping unit may be overloaded. Therefore, to detect damage to the tamping unit as early as possible, time-consuming and costly inspection and maintenance work is carried out regularly.

[0003] Tamping units and methods for track bed preparation are known, for example, from GB 2,451,310 A, from EP 2 770 108 A1, from EP 3 239 398 A1, from WO 2014 / 102401 A1, from WO 2017 / 097390 A1 and from WO 2017 / 129215 A1. Summary of the invention

[0004] The invention is based on the objective of creating a method for operating a tamping unit of a track construction machine that increases the reliability and cost-effectiveness of the tamping unit in operation.

[0005] This problem is solved by a method with the features of claim 1. According to the invention, it has been found that by accelerating at least one part of the tamping unit and by recording at least one measured variable correlated with the acceleration, the damage state of a tamping pick of the tamping unit designed to interact with the track bed can be determined based on the at least one measured variable. The at least one part of the tamping unit can be understood to be a component or part of a component of the tamping unit. The tamping unit can comprise a frame, at least two tamping pick supports attached to the frame and movable relative to it, and a tamping pick drive for moving the at least two tamping pick supports relative to the frame. The tamping pick can be attached to each of the at least two tamping pick supports.The at least two tamping tines are subject to particularly high stress during operation of the tamping unit. They are therefore exposed to significant wear, making breakage a possibility. If one of the at least two tamping tines breaks, track compaction is only partial and thus insufficient. By detecting damage to the at least two tamping tines promptly and reliably, they can be replaced as soon as possible. Damage to the tamping unit, especially to the tamping tines, can thus be detected reliably and promptly after it occurs, particularly through automated means. By reliably and early detecting damage, overloading of functional components of the tamping unit and insufficient track compaction over undefined sections of track can be reliably prevented.Regular visual inspections of the tamping unit to determine its condition are no longer necessary. This allows the track construction machine, and especially the tamping unit, to be operated with exceptional reliability and cost-effectiveness.

[0006] Preferably, the tamping unit is displaceable in the vertical direction by means of a drive unit. The tamping unit can be accelerated as a whole, particularly by means of the drive unit. Acceleration of at least a part of the tamping unit can also be achieved by accelerating at least one of the components, in particular the unit frame and / or the at least two tamping pick supports and / or the at least two tamping picks and / or the tamping pick drive, or a part of this at least one component.

[0007] Acceleration can be achieved using the drive unit and / or a separate exciter drive and / or an exciter brake. The drive unit can include the tamping unit drive and the tamping pick drive. The exciter drive can be positioned anywhere on the tamping unit and operated independently of the track compaction. The exciter brake can be used to slow the movement of at least part of the tamping unit.

[0008] Acceleration can be discrete and / or cyclical. During acceleration, the speed of motion of at least one part can be increased and / or decreased.

[0009] To measure at least one quantity correlated with acceleration, a driving force required for acceleration and / or an acceleration itself can be measured. Driving force also includes a braking force required for deceleration. The at least one quantity can be measured at at least one part of the tamping unit. The at least one quantity can also be measured at a position spaced away from at least one part. The at least one quantity can also be a quantity correlated with the driving force, in particular hydraulic pressure in a hydraulic cylinder and / or current flow in an electric motor. The at least one quantity can also be a quantity correlated with acceleration, in particular velocity and / or angular velocity.

[0010] The acquisition of the at least one measured variable can be continuous over time or at discrete intervals. Determining the damage state can be done analogously or digitally. Preferably, the at least one measured variable is acquired at at least two, in particular at least three, and in particular at least four, measuring positions on the packing unit.

[0011] Determining the condition of the tamping unit can be done by differentiating between functionality and damage. A functional tamping unit is defined as an undamaged unit. The condition can also be determined by identifying the type, location, and / or severity of the damage. For example, the condition of at least one component of the tamping unit can be assessed. This approach has the advantage of allowing damaged components of the tamping unit to be identified and replaced quickly and reliably.

[0012] To determine the state of damage, a change in at least one measured variable can be determined. For example, the rate of change of at least one measured variable can also be used to determine the state of damage of the tamping unit. Gradual wear of the tamping unit over time can thus be distinguished from a sudden failure of the tamping unit, particularly of a component thereof.

[0013] A method according to claim 2 ensures the increased reliability and cost-effectiveness of the track construction machine. Damage to one of the at least two tamping picks can, for example, lead to a change in bearing clearance and / or a change in the mass of the tamping pick. With a constant drive force for accelerating the tamping pick, the at least one measured variable correlated with the acceleration changes along with the damage to the tamping pick. Damage to the tamping unit, in particular to one of the at least two tamping picks, can thus be detected particularly reliably by accelerating the at least two tamping picks. For track bed compaction, the at least two tamping picks can be accelerated by means of the drive unit, in particular relative to the unit frame. Preferably, the acceleration of the tamping picks is effected via the tamping pick drive.

[0014] The at least one measured variable can be acquired directly at the at least two tamping picks. The at least one measured variable can also be acquired at the at least two tamping pick supports and / or at the drive unit, in particular at the tamping pick drive, especially at a drive housing of the tamping pick drive, and / or at the assembly frame. The drive housing can at least partially enclose a gearbox of the tamping pick drive and is also referred to as a gearbox housing.

[0015] A method according to claim 3 ensures the increased reliability and cost-effectiveness of the track construction machine. The position and / or orientation of the tamping unit, in particular of a component of the tamping unit, can be detected particularly easily and reliably. The position can, for example, be the vertical position of the tamping unit relative to the unit carrier. The orientation can be a rotation angle of the tamping pick carrier. For example, sensors of the drive unit required for driving the tamping unit can be used to detect the at least one measured variable. The position and / or orientation can, for example, be detected by means of a position sensor and / or a rotary encoder. For example, a Hall sensor and / or a potentiometer and / or a cable length sensor and / or an ultrasonic sensor and / or a laser sensor can be used to detect the at least one measured variable.

[0016] A method according to claim 4 ensures the increased reliability and cost-effectiveness of the track construction machine. The acceleration of the at least one part is effected by means of the drive unit. The measured variable corresponding to the acceleration can be reliably recorded directly at the drive unit. The drive unit acts on the at least two tamping picks via the at least two tamping pick carriers. By recording the at least one measured variable at one of the at least two tamping pick carriers, it is recorded along the load flow between the drive unit and the at least two tamping picks that are subject to particularly high stress. In particular, damage to the at least two tamping picks can thus be detected with exceptional reliability.

[0017] The at least one measured variable can be an angular acceleration of the at least two tamping pick supports and / or a linear acceleration, in particular of the support bearing via which the at least one tamping pick support is connected to the tamping pick drive. The at least one measured variable can also be a displacement of the drive unit, in particular of the power unit drive and / or the tamping pick drive. The at least one measured variable can thus be acquired with particular robustness and reliability.

[0018] A method according to claim 5 ensures the reliability and cost-effectiveness of the track construction machine. The hydraulic pressure can be the pressure of a hydraulic fluid in the tamping pick drive and / or the power unit drive. The hydraulic pressure can thus correlate with the drive force. Since the drive force correlates with the acceleration via the inertia of the tamping unit, at least one measured variable can be determined particularly easily and robustly using the hydraulic pressure.

[0019] Based on at least one measured variable, a torque and / or a force acting on at least two tamping picks can be determined. This at least one measured variable can also be determined in the form of the drive force and / or drive torque provided by the drive unit. The damage state of the tamping unit can be determined based on a change in the force and / or torque.

[0020] A method according to claim 6 ensures the increased reliability and cost-effectiveness of the track construction machine. In the reset position, the tamping unit is disengaged from the track bed. By acquiring the at least one measured variable in the reset position, the influence of the track bed on the acceleration of the at least one part of the tamping unit can be eliminated. For example, a varying condition of the track bed along the track thus has no influence on the at least one measured variable. The damage condition of the tamping unit can therefore be detected particularly robustly and reliably.

[0021] A method according to claim 7 ensures the reliability and cost-effectiveness of the track construction machine. The at least one reference parameter can correspond to the at least one measured parameter for a specific damage condition. Preferably, the at least one reference parameter corresponds to the at least one measured parameter for the functional state and / or for the damaged state of the tamping unit and / or for the damaged state of at least one component of the tamping unit. By comparing the at least one measured parameter and the at least one reference parameter, a damage condition of the tamping unit that deviates from its functional state can thus be reliably determined.

[0022] Preferably, the at least one measured variable is compared with several reference variables. At least two reference variables can correspond to several specific damage states. By comparing the at least one measured variable with the reference variables, it is thus possible to determine not only whether, but also to what extent, at which location, and in which component damage to the packing assembly is present.

[0023] Preferably, the at least one reference parameter is determined by recording the at least one measured parameter under a specific damage condition. The at least one reference parameter can also be determined once, particularly during installation and / or after maintenance of the tamping unit. The at least one reference parameter can be determined regularly, particularly after at most 100, particularly after at most 10, and particularly after each tamping cycle. A tamping cycle comprises moving the tamping unit from the reset position to the engagement position and back to the reset position. The at least one reference parameter is thus available for later comparison with the at least one measured parameter.This also advantageously achieves the fact that at least one reference size can be individually adapted to the respective tamping unit, in particular to the individual kinematic and mechanical properties of the tamping unit, and especially to typical wear.

[0024] A method according to claim 8 ensures the reliability and cost-effectiveness of the track construction machine. Damage to the tamping unit can be determined particularly easily and reliably if the at least one measured variable deviates from the at least one reference variable, in the form of a previously acquired at least one measured variable. The reference variable can also comprise several measured variables acquired at an earlier time. Alternatively, several measured variables acquired at different times can be compared with the at least one reference variable to determine the state of damage. The determination of the state of damage is thus particularly robust against random measurement deviations.

[0025] To determine the at least one reference quantity based on the at least one measured quantity, the at least two tamping picks can be removed from the tamping unit before it is operated.

[0026] A method according to claim 9 ensures the increased reliability and cost-effectiveness of the track construction machine. For example, the at least one measured variable can be the position and / or the orientation of the at least one part. By determining the time course of the at least one measured variable, the acceleration of the at least one part can be inferred from the position and / or orientation. Acquiring the at least one measured variable is particularly simple and robust.

[0027] The temporal profile allows for the detection of changes in at least one measured variable. For example, it can be determined how worn the tamping unit, particularly a single component of the tamping unit, already is and / or whether there has been sudden damage to the tamping unit, especially a breakage of one of the at least two tamping picks.

[0028] For example, to determine the state of damage, the amplitude and / or phase shift and / or frequency of at least one measured quantity can be determined. For example, the amplitude of a linear acceleration and / or an angular acceleration can be determined to determine the state of damage. Preferably, a phase shift of a linear acceleration and / or an angular acceleration is determined to determine the state of damage of the packing unit.

[0029] A method according to claim 10 ensures the increased reliability and cost-effectiveness of the track construction machine. The structural model preferably includes information about the geometric design and / or the bearings and / or the materials, in particular the density and / or the stiffness, of the tamping unit. Based on the structural model and the at least one measured parameter, the state of damage can be determined with particular reliability, and / or the extent of the damage can be ascertained. For example, the structural model can be used to determine which component, in particular whether the at least two tamping picks and / or a bearing point and / or the drive unit, is damaged and / or how severely it is damaged. In addition to the state of damage, the wear condition of the tamping unit can also be determined.The operational capability of the tamping unit can thus be exploited to a particularly large extent, thereby increasing the economic efficiency of the track construction machine.

[0030] A method according to claim 11 ensures the increased reliability and cost-effectiveness of the track construction machine. Damage to the tamping unit is preferably detected when the at least one measured variable exceeds the at least one threshold value. For example, the at least one measured variable may be low when the tamping unit is functioning normally and increase when the tamping unit is damaged. When the predetermined at least one threshold value is exceeded, the damage can be determined directly, particularly without further comparison with other values. The threshold value can be fixed. The damage can thus be determined particularly easily and reliably.

[0031] The at least one sensor for detecting the at least one measured quantity can, for example, be mounted on the tamping unit at a distance from its center of gravity. The at least one sensor can be configured as an accelerometer to detect acceleration in the vertical direction. When the tamping unit is functioning correctly, the acceleration acting on the at least one sensor is low. If the at least two tamping tines break, the acceleration of the at least one sensor in the vertical direction can increase significantly. If the at least one threshold value is exceeded, damage to the tamping unit can be detected.

[0032] To determine the damage to the packing unit, a difference between the measured value and the reference value can also be compared with a threshold value.

[0033] A method according to claim 12 ensures the increased reliability and efficiency of the track construction machine. By interrupting the operation of the tamping unit after detecting damage, insufficient compaction of the track bed and excessive stress on the tamping unit can be prevented. Upon detection of damage, a signal, in particular a warning tone and / or a visual signal, can also be provided to the user. Advantageously, this ensures that the user notices the damage to the tamping unit promptly after it occurs.

[0034] The following details and features of the process can be combined arbitrarily with each other and with the features already mentioned:

[0035] Based on at least one measured parameter, a loss of mass in the packing unit, particularly within its dynamic system, can be inferred. The degree of damage to the packing unit can then be determined based on this mass loss.

[0036] Based on at least one measured parameter, a movement pattern of the packing unit, in particular of a part of the packing unit, can be determined. The degree of damage to the packing unit can be determined based on a change in the movement pattern.

[0037] The invention is further based on the objective of creating a tamping device for track bed compaction that exhibits increased reliability and cost-effectiveness in operation.

[0038] This problem is solved by a stuffing device with the features of claim 13. The advantages of the stuffing device according to the invention correspond to the advantages of the method according to the invention. The stuffing device can be further developed, in particular, with the features of at least one of claims 1 to 12. Preferably, the stuffing unit is mounted on the unit carrier so as to be displaceable in the vertical direction. The at least one sensor can be configured as an acceleration sensor and / or as a pressure sensor and / or as a position sensor and / or as a rotary encoder and / or as a current sensor. The at least one sensor is preferably in signal communication with the evaluation unit. The stuffing device can have a control unit for controlling the drive device and / or for signaling a damage condition of the stuffing unit. For signaling the damage condition, the control unit can have a user interface.Preferably, the control unit is configured to interrupt the operation of the stuffing device, in particular the stuffing unit, upon receiving a signal from the evaluation unit indicating damage. The control unit can also be configured to output a signal, in particular an audible signal and / or a visual signal, to the user via the user interface when the evaluation unit signals damage to the stuffing unit.

[0039] The invention is further based on the objective of creating a track construction machine with a tamping device that exhibits increased reliability and economy.

[0040] This problem is solved by a track construction machine with the features of claim 14. The advantages of the track construction machine according to the invention correspond to the advantages of the tamping device according to the invention. The track construction machine can be further developed, in particular, with the features of at least one of claims 1 to 13. Brief description of the drawings

[0041] Further features, advantages, and details of the invention will become apparent from the following description of several exemplary embodiments. These show: Fig. 1 a schematic representation of a rail-guided track construction machine with a tamping device for track bed compaction, Fig. 2 a schematic front view of the tamping device in Fig. 1 , wherein a tamping unit of the tamping device is arranged in a reset position in which four tamping picks of the tamping unit are out of engagement with a track bed, Fig. 3 a schematic front view of the tamping device in Fig. 1 , wherein the tamping unit is arranged in an engagement position in which the four tamping picks are in engagement with the track bed, Fig. 4 a schematic side view of the tamping device in Fig. 1 , wherein the tamping unit is arranged in the engagement position, Fig. 5 Linear acceleration curves at a tamping pick drive of the tamping unit over time and pointer diagram for a functioning tamping unit, Fig. 6 Linear acceleration curves at the tamping pick drive over time and pointer diagram for a damaged tamping unit, Fig. 7 Angular acceleration curves of the tamping unit over time and pointer diagram for the functioning tamping unit, Fig. 8 Angular acceleration curves of the tamping unit over time and pointer diagram for the damaged tamping unit, Fig. 9 A schematic front view of a tamping unit according to a further embodiment with a tamping pick drive and two position sensors arranged on the tamping pick drive and Fig.10. A tamping unit according to a further embodiment, wherein the tamping pick drive comprises two hydraulic cylinders and wherein a pressure sensor is arranged on each of the two hydraulic cylinders. Description of the embodiments

[0042] A track construction machine 1 comprises a machine frame 2, at least two axles 3 mounted on the machine frame 2, a machine drive 4, and a tamping device 5 for track bed compaction. The axles 3 are spaced apart from each other along a horizontal x-direction on the track construction machine 1. The x-direction, together with a vertical z-direction and a horizontal y-direction, forms a machine-fixed coordinate system. Rail-guided wheels 6 are rotatably mounted on the axles 3. The machine drive 2 is designed to rotate the wheels 6 of at least one of the axles 3.

[0043] The tamping device 5 comprises an aggregate carrier 7, a tamping unit 8 mounted on the aggregate carrier 7, a drive device 9, a sensor 10, and an evaluation unit 11. A linear guide 12 is arranged between the aggregate carrier 7 and the tamping unit 8. The tamping unit 8 can be displaced along the z-direction relative to the aggregate carrier 7 via the linear guide 12.

[0044] The drive unit 9 comprises a unit drive 13 and a tamping pick drive 14. The unit drive 13 acts between the unit carrier 7 and the tamping unit 8 and provides a unit force FA for displacing the tamping unit 8 relative to the unit carrier 7. The tamping unit 8 has a unit frame 15. Two tamping pick supports 16 are attached to the unit frame 15 at intervals in the x-direction. The tamping pick supports 16 are each rotatably mounted on the unit frame 15 via a support axis 17 oriented parallel to the y-direction.

[0045] The tamping pick drive 14 is designed as a linear drive and acts between the unit frame 15 and one of the tamping pick supports 16. The tamping pick drive 14 has a hydraulic drive and an eccentric drive. The hydraulic drive ensures a high displacement amplitude at a low displacement frequency. The eccentric drive is designed to provide a low displacement amplitude and a high displacement frequency, in particular a compaction frequency fV. Both the hydraulic drive and the eccentric drive act between the unit frame 15 and the respective tamping pick support 16. The tamping pick drive 14 is designed to provide a drive force FV at the respective tamping pick support 16. Two tamping picks 18 are mounted on the underside of each tamping pick support 16.The driving force FV can thus be transferred to a track bed 19 via the respective tamping pick carrier 16 and the tamping picks 18 attached to it.

[0046] The sensor 10 is connected to the evaluation unit 11 via a signal line 20. The evaluation unit 11, in turn, is connected to a control unit 21. The control unit 21 has a user interface 22 for exchanging information with a user. The evaluation unit 11 includes a storage device 23 for storing at least one reference value.

[0047] The sensor 10 is designed as an acceleration sensor and is arranged on a drive housing 24 of the tamping pick drive 14. The sensor 10 is designed to detect linear accelerations a = [ax , ay , az ] in the x-direction, in the y-direction and in the z-direction, as well as to detect angular accelerations α = [α x , α y , α z ] about the x-direction, the y-direction and the z-direction.

[0048] The operation of the track construction machine 1 and the tamping device 5 are described below: To lay or maintain the track bed 19, the track construction machine 1 is moved along a track 25 in the x-direction by means of the machine drive 4. A central axis 26 of the tamping device 5 is positioned centrally above a sleeper 27 arranged on the track bed 19 to support the track 25.

[0049] At the start of the track bed compaction process, the tamping unit 8 is in a reset position 28. The tamping unit 8 is at an upper end position of the linear guide 12, and the tamping picks 18 attached to the tamping unit 8 are out of engagement with the track bed 19. The tamping unit 8 is functional and shows no damage.

[0050] The tamping pick drive 14 is activated by a signal from the control unit 21. The tamping pick drive 14 is connected to the two tamping pick carriers 16 via support bearings 29. The tamping pick drive 14 transmits a cyclic lifting motion to the respective tamping pick carrier 16. The rotatably mounted tamping pick carriers 16 move cyclically about their respective carrier axis 17. The tamping picks 18, spaced apart from each other in the x-direction, move cyclically towards and away from each other.

[0051] The cyclic stroke motion transmitted from the tamping pick drive 14 to the two tamping pick supports 16 has a compression frequency fV of 35 to 45 Hertz. Bearing forces are transmitted via the bearing axes 17 of the tamping pick supports 16 and via the drive housing 24 of the tamping pick drive 14 to the assembly frame 15, exciting the tamping unit 8 to vibrate at an assembly frequency fA. The assembly frequency fA essentially corresponds to the compression frequency fV. The assembly frequency fA also acts on the drive housing 24 and sets it into vibration.

[0052] The sensor 10 attached to the drive housing 24 detects six measured quantities in the form of the vector of linear accelerations a and the vector of angular accelerations. α The accelerations detected by sensor 10 a , αare dependent on a mass m A of the tamping unit 8, in particular on the masses m S of the respective tamping picks 18. When the two tamping pick carriers 16 are driven by means of the tamping pick drive 14, the driving force FV in the return position 28 is only opposed by the inertial force FT. For a linear acceleration of a mass m, the following generally applies: F V = F T = m ⋅ a

[0053] This shows that a change in mass m also changes the acceleration a and / or the driving force FV. The same applies analogously to angular acceleration: M V = M T = I m ⋅ α

[0054] MV is a driving torque, I is an inertial torque, and MT is a moment of inertia acting due to the angular acceleration α and the inertial torque I. In particular, the aggregate amplitudes are S a the linear accelerations a and the aggregate amplitudes S a the angular accelerations αdepending on the mass m A of the stuffing unit 8, in particular on the mass m S of the stuffing picks 18.

[0055] The trends of the measured quantities a , α are determined for the undamaged packing unit 8 and used as reference values ​​in the storage medium 23 a 0 , α The reference values ​​and the further values ​​derived from them are subsequently marked with the index 0. Fig. 5 are the curves of the linear accelerations a The phase of the functioning tamping unit 8 is shown over a time t. A phasor diagram provides additional information about a phase shift. ϕ a,0 = [ϕ a,x,0 , ϕ a,y,0 , ϕ a,z,0 ] of the linear accelerations a 0 . In Fig. 7 are the curves of the angular accelerations α0 for the undamaged, functional tamping unit 8 over time t together with a phasor diagram to represent the phase shifts ϕ α,0 = [ϕ α,x,0 , ϕ α,y,0 , ϕ α,z,0 ] between the angular accelerations α 0 shown.

[0056] At the beginning of a tamping cycle to compact the track bed 19, the tamping unit 8 is moved towards the track bed 19 by means of the unit drive 13 in the opposite direction to the z-direction.

[0057] In an engagement position 30, the tamping unit 8 is located at a lower end of the linear guide 12. The four tamping picks 18 penetrate the track bed 19. The tamping unit 8, arranged in engagement position 30, is in Fig. 3 and Fig. 4 The operation of the tamping pick drive 14 is maintained during the movement between the return position 28 and the engagement position 30, as well as in the engagement position 30. In addition to the high-frequency movement of the tamping pick 18 at the compaction frequency fV, the tamping picks 18, which are spaced apart from each other in the x-direction, are moved towards each other in the engagement position 30 by means of the tamping pick drive 14. The compaction of the track bed 19 is achieved by the superposition of these two movement components of the tamping picks 18.

[0058] During the compaction of the track bed 19, high static and dynamic loads act on the tamping unit 8, in particular on the tamping picks 18. This leads to damage to the tamping unit 8 through a breakage of one of the four tamping picks 18.

[0059] The tamping unit 8 is moved back from the engagement position 30 to the return position 28 by means of the unit drive 13. The tamping cycle is thus completed. Before the start of the next tamping cycle, the track construction machine 1, in particular the tamping device 5, is moved in the x-direction such that the central axis 26 is positioned centrally above the nearest sleeper 27 in the x-direction.

[0060] The breakage of the tamping pick 18 reduces its mass mS. Consequently, the mass of the tamping unit mA is also reduced. This alters the inertial forces FT and moments of inertia MT opposing the driving force FV. This, in turn, affects the vibration behavior of the tamping unit 8.

[0061] At the beginning of the next packing cycle, the measured values a , αThe measured values ​​a, α, and the resulting further quantities are acquired anew by means of sensor 10. The measured values ​​a, α, acquired from the damaged packing unit 8, and the further quantities derived from them, are subsequently denoted by the index 1. To determine a damage state, the current measured values ​​a1, α1 are compared with the reference values ​​a0, α0. In particular, the unit amplitudes Sa,1, Sα,1 and the phase shifts ϕa,1, ϕα,1 of the measured values ​​a1, α1 are compared with the unit amplitudes Sa,0, Sα,0 and the phase shifts ϕa,0, ϕα,0 of the reference values ​​a0, α0. Damage to the packing unit 8 is detected if a difference between the measured unit amplitudes Sa,1, Sα,1 and the reference values ​​of the unit amplitudes Sa,0, Sα,0 reaches or exceeds a threshold value SWS. Damage to the packing unit 8 is also detected if a difference between the measured phase shifts ϕ a,1 , ϕ α,1 and the reference quantities of the phase shifts ϕ a,0 , ϕ α,0 a threshold SW ϕ exceeds the phase shifts. Damage to the tamping unit is therefore determined if the following holds: S 1 − S 0 ≥ SW S φ 1 − φ 0 ≥ SW φ

[0062] In the Fig. 6 The curves of the linear accelerations a 1 detected at sensor 10 for the damaged tamping unit 8 with the broken tamping pick 18 are shown over time. From the Fig. 6 The aggregate amplitudes S a,1 and the phase shifts ϕ a,1 of the linear accelerations emerge. In Fig. 8 are the curves of the angular accelerations α 1 of the damaged stuffing unit 8 is shown over time t. From the Fig. 8 the aggregate amplitudes S α ,1 and the phase shifts ϕ α,1 of the angular accelerations α 1 stand out.

[0063] From the Fig. 5 bis Fig. 8 It becomes apparent that the breakage of a tamping pick 18 and the associated reduction in the mass m A of the tamping unit leads to a significant change in the measured quantities. a 1 , α 1 compared to the reference values a 0 , α 0 leads to the following. Damage to the tamping unit 8, in particular the loss of the tamping pick 18, can thus be reliably detected.

[0064] The evaluation unit 11 detects damage to the packing unit 8. Based on a signal from the evaluation unit 11, the control unit 21 interrupts the operation of the packing unit 8. The user is notified of the damage to the packing unit 8 via the user interface 22.

[0065] in Fig. 9 A further embodiment of the tamping device 5 is described. In contrast to the previous embodiment, the tamping device 5 comprises two sensors 10, which are designed as position sensors. The two sensors 10 are each arranged on a tamping pick drive 14 and are designed to detect a stroke s of the tamping pick drive 14. The sensors 10 are in signal communication with the evaluation unit 11 via a signal line 20.

[0066] The measured quantity s is recorded in the form of the actuator position s. Based on the measured quantity s, the actuator speed s' = ds / dt is first determined by calculating the change in actuator position ds over a discrete time step dt. Based on the change in actuator speed ds' over a discrete time step dt, the actuator acceleration s" = d / dt is then determined.

[0067] To determine whether the tamping unit 8 is damaged, the actuating acceleration s" is used in the same way as in the previous embodiment with the accelerations. a , α .

[0068] As an alternative to recording the stroke s, a position in the x-direction and / or in the y-direction and / or in the z-direction, for example of the support bearing 29 or another component of the tamping unit 8, can also be recorded. An orientation about the x-direction and / or about the y-direction and / or about the z-direction, for example of one of the tamping pick supports 16, can also be recorded.

[0069] Another embodiment of the stuffing device 5 is described in Fig. 10As shown. In contrast to the preceding embodiments, the tamping device 5 has two sensors 10 in the form of pressure sensors. The two sensors 10 are designed to detect the pressure of a hydraulic fluid in each of the hydraulic cylinders 31 of the tamping pick drive 14. The two sensors 10 are connected to the hydraulic cylinders 31 via pressure lines 32. The sensors 10 are in signal communication with the evaluation unit 11 via the signal lines 20.

[0070] To determine damage to the packing unit 8, a time-dependent pressure profile p is compared with a time-dependent reference pressure p₀. A change in the mass m of the packing unit 8 leads to a change in the inertial force FT and thus to a change in the driving force FV required for acceleration a. Damage to the packing unit 8 is detected if the magnitude of the difference between the measured quantity p and the reference quantity p₀ exceeds a threshold value SW p.

[0071] According to a further embodiment, a structural model of the tamping unit 8 is stored in the evaluation unit 11. The structural model includes the components of the tamping unit 8, their masses, their bearings, as well as their materials and stiffnesses. Based on the drive force FV acting on the tamping unit 8 and the at least one measured parameter, a , αThe structural model allows conclusions to be drawn about specific damage to the packing unit 8. For example, the reduction in the mass mS of a particular packing plug 18 can be detected. Based on at least one measured parameter a , α , p, s and based on the structural model stored in the evaluation unit 11, in addition to determining the damage, a type of damage, in particular a position of the damage on the stuffing unit 8, is determined.

[0072] By transmitting the damage status of the packing unit 8 based on at least one measured parameter a , αDamage to the tamping unit 8 can be detected particularly reliably. In particular, the damage can be detected automatically by means of the evaluation unit 11. The need for regular visual inspection of the tamping unit 8 is eliminated, and the risk of operating the tamping unit 8 in a damaged state, where sufficient compaction of the track bed 19 cannot be guaranteed and where undamaged components of the tamping unit 8 could be overloaded, is avoided. The track construction machine 1, and especially the tamping unit 8, is therefore particularly efficient and economical in operation.

Claims

1. A method of operating a tamping unit of a track maintenance machine, comprising the steps: - providing the track maintenance machine (1) with the tamping unit (8) on a track bed (19), - accelerating at least a part (18, 24) of the tamping unit (8), - recording at least one measuring value (a, α, p, s) correlating to the acceleration, and - determining a damage condition of the tamping unit (8) by means of the at least one measuring value (a, α, p, s), characterized in that, by means of the at least one measuring value (a, α, p, s), a damage condition of a tamping tine (18) for interaction with the track bed (19) is determined.

2. A method according to claim 1, characterized in that the at least one part (18, 24) is a tamping tine (18) for interaction with the track bed (19).

3. A method according to one of claims 1 to 2, characterized in that the at least one measuring value (a, α, p, s) is a position and / or an orientation.

4. A method according to one of claims 1 to 3, characterized in that the at least one measuring value (a, α, p, s) is recorded at a tamping tine carrier (16) of the tamping unit (8) and / or at a drive device (9) of the tamping unit (8).

5. A method according to one of claims 1 to 4, characterized in that the at least one measuring value (a, α, p, s) is a hydraulic pressure (p) for accelerating the at least one part (18, 24).

6. A method according to one of claims 1 to 5, characterized in that the recording of the at least one measuring value (a, α, p, s) takes place in a reset position (28) in which the tamping unit (8) is not in engagement with the track bed (19).

7. A method according to one of claims 1 to 6, characterized in that, for determining the damage condition, the at least one measuring value (a, α, p, s) is compared to at least one reference value (a0, α0, p0, s0).

8. A method according to claim 7, characterized in that the at least one reference value (a0, α0, p0, s0) is determined by means of the at least one measuring value (a, α, p, s) in an undamaged state of the tamping unit (8).

9. A method according to one of claims 1 to 8, characterized in that the determination of the damage condition takes place by way of a chronological progression of the at least one measuring value (a, α, p, s).

10. A method according to one of claims 1 to 9, characterized in that the determination of the damage condition takes place by way of a structural model of the tamping unit (8).

11. A method according to one of claims 1 to 10, characterized in that, when at least one threshold value (SWa, SWα, SWp, SWs) of the at least one measuring value (a, α, p, s) is exceeded, a damaging of the tamping unit (8) is detected.

12. A method according to one of claims 1 to 11, characterized in that, after detection of a damage, an operation of the tamping unit (8) is interrupted.

13. A tamping device for track bed consolidation, comprising - a unit carrier (7), - a tamping unit (8) displaceably mounted on the unit carrier (7), - a drive device (9) for providing a driving force (Fv) and for causing an acceleration (a, α) of at least one part of the tamping unit (8), - at least one sensor (10) for recording at least one measuring value (a, α, p, s) correlating to the acceleration (a, α), - an evaluation unit (11) for determining a damage condition of the tamping unit (8) by means of the at least one measuring value (a, α, p, s). characterized in that, the evaluation unit (11) is designed to determine a damage condition of a tamping tine (18) for interaction with the track bed (19).

14. A track maintenance machine, comprising - a machine frame (2), - at least two axles (3), supported on the machine frame (2), with rail-guidable wheels (6) arranged thereon, - a machine drive (4) for rotary actuation of the wheels (6) of at least one of the axles (3), and - at least one tamping device (5) according to claim 13, mounted on the machine frame (2).