AT518072A4 - Tamping unit for a tamping machine - Google Patents

Abstract

It is a tamping unit (3) for a track tamping machine with arranged on a in a Stopfaggregatrahmen guided, carriers (23), designed as rocker arm Stopfwerkzeugpaaren proposed for immersion in a ballast bed (19) certain lower tufting ends (17) with a vibration drive (4, 5) can be driven in opposite directions and can be supplied hydraulically to one another. To increase the stability of the tamping unit, it is proposed that each of the tamping tools (6) of a pair of tamping tools form a hydraulic cylinder (4, 5), wherein the hydraulic cylinders (4, 5) form the auxiliary drive as well as the vibration drive of the tamping tools (6) and the control the hydraulic cylinder (4, 5) is oil-flow-dependent or pressure-dependent, and in that hydraulic cylinder control valves (12), which are arranged directly on the hydraulic cylinder (4, 5), are provided for actuating the hydraulic cylinders (4, 5).

Description

The invention relates to a tamping unit for a track tamping machine with arranged on a in a Stopfaggregatrahmen height adjustable, arranged carrier, designed as rocker Stopfwerkzeugpaaren whose immersion in a ballast certain lower tufting ends with a vibration drive counter driven and hydraulically to each other beinellbar, each the tamping tools of a Stopfwerkzeugpaares is associated with a hydraulic cylinder, wherein the hydraulic cylinders form both the Beistellantrieb and the vibration drive of the tamping and Hydraulikzylinderansteuerventile are provided for actuating the hydraulic cylinder, which are preferably arranged directly on the hydraulic cylinder. In addition, an adjustable opening width cylinder or opening width distance sensor may be provided for continuous opening width adjustment.

Tamping units penetrate with gravel tools the gravel of a track bed in the area between two sleepers (intermediate compartment), in the area of the support of the threshold in the ballast under the rail and compact the ballast by a dynamic vibration of the tamping between the opposable tamping pegs that can be provided to each other. Tamping units can plug one, two or more sleepers in one work cycle (DE 24 24 829 A, EP 1 653 003 A2).

According to the teaching of EP 1 653 003 A2, the auxiliary drives acting as a linear drive are designed in such a way that they not only provide a linear supply movement, but at the same time also in a manner known from AT 339 358, EP 0 331 956 or US Pat. No. 4,068,595 generate the vibration required for the tamping pimples. Thus, the additional speed, the vibration amplitude, its shape and the frequency can be specified. Patent AT 513973 B1 describes a hydraulic linear drive of the auxiliary cylinders, wherein each of the auxiliary cylinders is assigned a displacement sensor for determining the hydraulic cylinder position.

The movements of a tamping unit include the vertical immersion of the tamping pick in the ballast, the Beistellbewegung in which the tamping ends are closed to each other and the superimposed dynamic oscillation which causes the actual compaction of the ballast grains. It is known for the Beistellbewegung to use hydraulic cylinder, which are connected via connecting rods with a vibration wave with eccentricity and superimpose the Beistellbewegung the vibratory vibration (AT 369 455 B). These vibration shafts and connecting rods are mounted on roller bearings, which regularly require more expensive maintenance. Other known solutions use linear excitation via hydraulic cylinders. Two hydraulic cylinders are mechanically coupled in series. The one hydraulic cylinder performs the Beistellbewegung, the other the vibratory movement. The size of the resulting vibration is determined mechanically and by the hydraulic excitation. The size of the amplitude can not be adjusted freely.

From the literature (Lichtberger, Bernhard: Fully hydraulic plugging - a new technology for efficient maintenance, El Railway Engineer, July 2015, S18-22) is also known that the gravel can be compacted depending on its properties only up to a certain compacting force. With further compression (further closing of the stuffing tools), the compression can not be further increased, the ballast evades and flows into the leader or other area. This unfavorably reduces the compacted contact surface below the threshold. It is also known from the above literature that the compaction work is an expression of the ballast bed hardness.

Optimal stop frequencies for compaction are known to be between 25-40 Hz, with penetration of the tamping pick in normal ballast with higher frequencies is easier, since only a small immersion shock occurs and thus the stress on the bearings of the tamping unit can be reduced. This is no longer the case for irregular heavily contaminated hard gravel beds. Here are other settings of frequency and amplitude advantageous.

The tamping units in use today have a very high and costly maintenance. Typically, the units are at least partially overhauled and maintained every season. After 1-2 overhauls, the units must be replaced by new ones. In addition, it is known to equip tamping units with rotating vibration waves with flywheel, so that the frequency does not drop too much with increasing compaction of the ballast. It is also known that in the control of the auxiliary cylinder, the amplitude decreases due to the elasticity of the hydraulic hoses and thus the compression effect decreases. From various studies it is known that decreasing Stopfamplituden or a decreasing compression frequency affect the compression and also reduce the penetration into the ballast. In the case of the embodiment of a linear drive with displacement sensor described under AT 513973 B1, the disadvantages described are indeed avoided, but the displacement sensor installed in the hydraulic cylinder is subject to very high accelerations and therefore increases the service life costs. On the other hand, the regulation of the amplitude and addition movement with the aid of a displacement sensor corresponds to an indirect method and complicates it. Proportional valves or servo valves are designed for direct pressure or flow control or a combination of both. These are usually controlled electrically via a current loop (0-20mA, 4-20mA) or a voltage input (0-10V, ± 10V).

The invention is therefore the object of tamping units of the type described with simple means such that the stability of the vibration drive by the use of only one Hydraulikbeistellzylinders is significantly increased, but at the same time on the use of highly loaded displacement sensors in the cylinder and an indirect complicated control the disadvantages associated with it can be dispensed with.

The invention solves the problem by the fact that in

Hydraulic cylinder oil supply circuit at least one means for determining the flow of oil, in particular an oil flow sensor, is provided and that the

Control of the hydraulic cylinder in dependence of the oil flow data oil flow dependent so done that a predetermined Beistellweg the stuffing tools is achieved. Each of the stuffing tools of a Stopfwerkzeugpaares is associated with a hydraulic cylinder, wherein the hydraulic cylinder form the Beistellantrieb as well as the vibration drive of Stopfpickel and the control of the proportional or servo valve takes place directly via the electrical valve input. At this control input, the signals are now electrically specified so that the desired flow through the Beistellzylinder arise.

The means for determining the oil flow allow the controllability of the hydraulic cylinder (positions). In an advantageous case, the flow in the Hydraulikzylinderansteuerventil be measured, for example by an evaluation of the measured position of the valve piston in the valve.

To set any opening width of Stopfaggregates a stopper auxiliary cylinder is installed which is hydraulically biased. On the other hand, the two cylinder pressures are measured by means of pressure sensors. When the unit is started up, the vibration is switched off and the hydraulic cylinders are opened. When the unit reaches the upper position, the unit moves together until a mechanical stop on the auxiliary cylinder on the piston side strikes the stopper auxiliary cylinder previously set by the operator. As a result, the pressure in the auxiliary cylinder increases at short notice. This increase in pressure is detected and evaluated by the controller and stopped the Beistellbewegung. Alternatively, with e.g. a laser distance sensor or another distance sensor to stop the opening width are measured and at the predetermined target width of the auxiliary cylinder is stopped when moving together and held in this position. Another alternative is to install so-called shock valves which are e.g. be swung over by compressed air cylinder as mechanical stops. The hydraulic cylinder piston rod is then retracted until the mechanical stop is reached. In this case, one has no continuously adjustable opening width but only two opening widths. This corresponds to the most commonly used tamping units today which still have shock valves. If distance sensors are used to control the opening width, then these can also be used to measure the auxiliary travel.

According to the invention, a single common hydraulic cylinder is used for the Beistellbewegung and the vibratory movement of at least one stuffing pickle (possibly also of several synchronously driven stuffing pickles of several pairs of stuffing needles).

To operate the hydraulic cylinder recommend

Hydraulikzylinderansteuerventile particular servo or proportional valves, which are arranged directly on the hydraulic cylinder. The hydraulic lines should be as short as possible, so that the elasticity, the storage effect (damping) of the hydraulic hoses under the impact load, is kept low. Typical requirements are amplitudes of 3-6 mm at the tamping ends at a maximum frequency of 50 Hz. Compression amplitudes close to the upper limit are better, for example, for loose gravel (after track cleaning and track renewal or new track construction).

The control / regulation specifies the oscillation, the oscillation amplitude and the oscillation frequency, depending on the height and the supplementary position of the tufting ends. The linear addition movement corresponds to a constant oil flow with pressure on the A side of the valve. This constant oil flow Qßei is calculated with the desired addition speed vBei and the cylinder tube surface Az as follows

The required oil flow for the vibration generation is calculated as follows with the vibration amplitude A and the frequency f of the vibration

The nominal flow rate is predetermined by an electrical signal course. For this purpose, for the linear Beistellbewegung required as above corresponding to the Beistellbewegung superimposed on the sign changing vibration oil flow. The amplitude of the AC voltage for the oil flow then corresponds to the vibration amplitude and the frequency of the AC voltage of the stop frequency.

If a pressure control is to be used instead of the flow control, the following relationship between pressure and flow applies:

Q ... actual volume flow

Qn ... Nominal flow Δρ ... Pressure drop per control edge Valve ΔρΝ ... Nominal pressure drop per control edge profile

The main advantage of the invention is the simple construction. In addition, the Stopfaggregatöffnungsweite, ie the distance between the tufting ends, infinitely adjustable and is any free preselection of the stop frequency, such as immersion of the pimples at 50 Hz for a low insertion shock and a compression at 35 Hz in working position to reduce wear and noise , easily possible. A continuous adjustment of the stuffing amplitude and its signal shape (rectangle, sine, triangle, sawtooth) allows an optimal adaptation to the respective superstructure conditions. If a control loop is provided, an automatic readjustment of the plug movement takes place in the event of resistance changes by the control loop, thus ensuring that the desired plug amplitudes and frequencies are maintained. Usually, the Beistellbewegung is controlled and / or regulated by the controller / regulation. But if the gravel is already highly compressed, then the

Actual movement forcibly deviate from the target movement. However, in order to be able to compress the ballast in a targeted manner, it is advisable for the control / regulation to readjust the oscillation, the oscillation amplitude and the oscillation frequency accordingly, depending on the comparison of the desired flow to the actual flow, in particular with a flow meter, the oil flow , With the help of the pressure sensors, the achieved compacting force can be measured. If the maximum possible degree of compression is reached, the optimal time is to stop the plug. Otherwise, the compacted support will be reduced in area by drainage of compacted ballast.

The compacting work is proportional to the ballast bed hardness. The compression work W can be indicated as follows from the measured flow rate, the tamping time and the measured cylinder pressure:

With the flow measurement and the pressure measurement in the hydraulic circuit, the compaction of the ballast bed can be calculated. For this, the measuring signals are numerically integrated as indicated.

With the invention, various modes of tamping or the Einzelpickelsysteme are possible, in particular different frequency, different amplitudes u. Like. For different gravel bed hardnesses. There are also statements about the condition of the ballast bed (loose, caked, dirty) on the compression work possible. On a change in ballast bed conditions can be reacted immediately and automatically. Thus, in casual bedding the Beistellgeschwindigkeit could be increased at the beginning and the amplitude can be increased. If the bedding becomes denser due to the plug, the amplitude and frequency can be readjusted continuously. The pressure measurement of the two chambers of the hydraulic cylinder allows the specification of the achieved compression (by specifying the compacting force). The compaction force measured in this way is indirectly also a statement about the quality of the ballast and the bedding conditions.

For example, rounded gravel can be not be as compacted as coarse-grained basalt. Normally, each cylinder is assigned a hydraulic cylinder control valve. For a Einschwollenstopfmaschine therefore eight, for a two-shaft tamping machine already sixteen and for a Dreischwellenstopfmaschine thirty-two cylinders with the associated Hydraulikzylinderansteuerventilen are required. In addition to the associated costs, the number of valves used naturally also increases the susceptibility to errors.

To reduce this error rate, it is proposed that at least two hydraulic cylinders are connected to a common Hydraulikzylinderansteuerventil, wherein between the Hydraulikzylinderansteuerventil and the hydraulic cylinders, a flow divider is provided. A then required, slightly larger valve requires less loss and heat output than would cause two individual. The flow divider divides the flow of oil into exactly two equal parts. It is also possible to connect several hydraulic cylinders to a Hydraulikzylinderansteuerventil, whereby the losses can be reduced again.

In the drawing, the subject invention is shown, for example. Show it

1 is a tamping unit according to the invention in side view,

2 is a detail of a tamping unit with a schematic hydraulic cylinder oil supply circuit in side view,

3 is a schematic of a side cylinder with specified vibration amplitude, FIG. 4 is a diagram of a side cylinder with Beistellgeschwindigkeit,

5 is a diagram for determining the effective oil flows,

6 shows a Ventilansteuerschema with operating points,

7 shows a schematic of a control / regulating device, and FIG. 8 shows a variant of a hydraulic cylinder oil supply circuit according to the invention.

A tamping unit 3 (FIG. 1, 2) for a tamping machine comprises, inter alia, tamping tool pairs 4, 5 with tamping tools 6, 17 arranged on a support 23 and designed as oscillating levers, with their bottom tufting ends 17 intended for immersion in a ballast bed 19 with a vibration drive 4, 5 driven in opposite directions and hydraulically to each other, with a Beistellweg 20, are settable. The stuffing tools 4, 5, 6, 17 are designed as two-armed levers. One arm of the respective stuffing tool 6 is formed by a tamping pick 17 and on this engages a hydraulic cylinder 5, the other end is mounted on a support 23. About pressure sensors 11, the cylinder pressures are measured. The cylinder 5 is electrically actuated via a servo valve or a proportional valve 12

Hydraulic cylinder oil supply circuit is an oil flow sensor 14th

The pressure is generated via a hydraulic pump 15. The oil is sucked by the pump 15 from the hydraulic tank 16 via the oil flow sensor 14 to the control valve 12. Depending on the control of the valve 12, either the A connection or the B connection is supplied with pressure.

The auxiliary movement takes place when the A-side is pressurized, the opening movement when the B-side is pressurized. The ballast 19 is compressed by the tamping 17 below the threshold 18. The compacting movement 20 of the pickle 17 consists of a continuous closing movement 22 and a superimposed oscillatory movement 21. A hydraulically preloaded position cylinder 8 with integrated displacement sensor 24 can be adjusted by the operator continuously to the desired opening width 25. When booting into working position now closes the side cylinder 5 until the mechanical stop 7 on the stop 9 occurs. The resistance generates a pressure peak in the auxiliary cylinder 5 which is measured via the pressure sensor 11. The electronics 25 detects this pressure peak and automatically switches off the further movement of the auxiliary cylinder 5. With this device, any desired opening width 25 can be set by the operator. The Beistellbewegung the Beistellzylinders 3 can be seen by 22.

Alternatively to the position cylinder 8 z. B. a non-contact laser distance meter 10 or another position sensor are used, which measures the distance of the mechanical stop 7. Upon reaching the predetermined desired opening width 25 of the auxiliary cylinder 5 is also switched off. In the upper working position the vibration is always switched off. 29 schematically indicates the position of the tamping unit 3 in the upper working rest position. The height Ah is called the stop depth. Figure 30 schematically illustrates a pivotable mechanical stop, often referred to as a flapper. Swiveled in, it delivers the normal opening angle as used for single sleepers. However, if there are double sleepers (with a rail joint) then the shock flaps 37 are swung out and the stuffing arms are opened further.

Fig. 3 shows schematically a side cylinder with the cylinder tube surface Az and the piston surface Ak. The auxiliary cylinder oscillates with the amplitude A.

4 schematically shows a side-by-side cylinder which moves as an adjunct to the additional speed vB. When working, the oscillation overlaps with the amplitude A and the continuous addition movement vB.

In the upper diagram (FIG. 5), the oil flow Qvib which is used for the vibration with the period T is plotted as a function of the time t. Pressure on valve port P-A is called compressing forward vibratory motion at the bottom of pimple 17. Pressure on valve port P-B means vibrating non-compressive retraction movement. The diagram in the middle shows the time course for the required oil flow QBei for a constant Beistellbewegung. Finally, in the lower diagram, the two oil flows are shown superimposed. The constant supply flow has the same effect as an offset for the vibration oil flow QvibA, Qvibß. The result is (see diagram below) so that an oil flow fluctuates between Qmm and Qmax.

Fig. 6 shows the control characteristic of a control valve. Applied vertically is the flow. Horizontal the control signal in%. Positive flow 2, P-A means

Pushing out the piston rod and thus compressing, negative flow 1, P-B means flow reversal and retraction of the piston rod. It can be seen from the diagram that the operating point is at Qsei and the oil flows for the oscillation are moving around this operating point. In the case shown, the setpoint with the additional frequency f would fluctuate between approx. -20% and 80%. The resulting flows would be Qmin with negative drive and Qmax with positive drive. The setpoint specification in% is carried out electrically, e.g. through a current loop of 0-20mA. 0mA (-100%) would have full negative modulation, at 10mA (0%) no flow would set and at 20mA (100%) full positive modulation.

Fig. 7 shows schematically a control / regulating device 25. To the control electronics 25, the pressure sensors 11, the flow sensor 14 and the position sensors 10, 24 are connected. The operator can enter via touch display 26 or a keyboard 28 the amplitude A, the frequency f and the additional speed vB. Via a control output, the control valve 12 is activated. The arithmetic unit can perform a desired-actual comparison 27 of the desired flow rate with the measured actual flow rate and adjust it so that the desired compression amplitude and the desired auxiliary speed result.

In the embodiment of FIG. 8, two hydraulic cylinders 4, 5 are connected to a common Hydraulikzylinderansteuerventil 12, wherein between the Hydraulikzylinderansteuerventil 12 and the hydraulic cylinders 4, 5, a flow divider 31 is provided. Between the flow divider 31 and the hydraulic cylinders 4, 5 each an oil flow sensor 14 is arranged. However, it could also be provided only an oil flow sensor upstream of the flow divider 31.

Claims (15)

claims 1. Stopfaggregat (3) for a track tamping machine with on one in a Stopfaggregatrahmen height adjustable out, carrier (23) arranged as rocker arm Stopfwerkzeugpaaren whose immersion in a ballast bed (19) certain lower tufting ends (17) with a vibration drive (4 , 5) can be driven in opposite directions and can be provided hydraulically with each other, wherein each of the stuffing tools (6) of a Stopfwerkzeugpaares a hydraulic cylinder (5) is assigned, wherein the hydraulic cylinders (4, 5) both the Beistellantrieb and the vibration drive of the stuffing tools (6) form and for actuation of the hydraulic cylinders (4, 5) are provided Hydraulikzylinderansteuerventile (12), which are preferably arranged directly on the hydraulic cylinder (4, 5), characterized in that in the hydraulic cylinder oil supply circuit at least one means for determining the oil flow, in particular an oil flow sensor (14), is provided and that the Anste Translation of the hydraulic cylinder (4, 5) depending on the oil flow rate oil flow-dependent. 2. Stopfaggregat according to claim 1, characterized in that the Stopfaggregatrahmen (23), a hydraulically preloaded stop cylinder (8) with stop (9) and pressure sensors (11) are constructed for pressure measurement of the cylinder pressures. 3. Stopfaggregat according to claim 1 and 2, characterized in that in the hydraulically preloaded stop cylinder (8), a displacement sensor (24) is integrated. 4. Stopfaggregat according to one of claims 1 to 3, characterized in that a displacement sensor (10) constructed as a laser distance meter is constructed which measures the opening width (25) of the auxiliary cylinder (4, 5). 5. Stopfaggregat according to one of claims 1 to 3, characterized in that a displacement sensor (10) constructed as an ultrasonic distance sensor is constructed which measures the opening width (25) of the auxiliary cylinder (4, 5). 6. Stopfaggregat according to one of claims 1 to 3, characterized in that a displacement sensor (10) constructed as a cable puller is constructed which measures the opening width (25) of the auxiliary cylinder (4, 5). 7. Stopfaggregat according to one of claims 1 to 6, characterized in that a fixed stop (30) on and is swingable, the two opening widths (25) of the auxiliary cylinder (4, 5) pretends. 8. Stopfaggregat according to one of claims 1 to 7, characterized in that the control / regulation (25) the oscillation (21), the oscillation amplitude (A) and the oscillation frequency (f) in dependence on, in particular with a flow meter (14) , measured flow predetermines. 9. Stopfaggregat according to one of claims 1 to 8, characterized in that the Hydraulikzylinderansteuerventile (12) are servo or proportional valves. 10. Stopfaggregat according to one of claims 1 to 9, characterized in that the hydraulic cylinder position of a control / regulation (25) in dependence of the flow (14, QSon) is predetermined. 11. Stopfaggregat according to one of claims 1 to 10, characterized in that a linear Beistellbewegung (vB) of the hydraulic cylinder (4, 5) is superimposed on a vibration (21). 12. Stopfaggregat according to claim 1 to 11, characterized in that the control / regulation (25), the oscillation (21), the oscillation amplitude (A) and the oscillation frequency (f), in dependence on the altitude (Ah) of the stuffing tine (17 ) pretends. 13. Stopfaggregat according to one of claims 1 to 11, characterized in that the control / regulation (25), the oscillation (21), the oscillation amplitude (A) and the oscillation frequency (f), in dependence on the pressure drop per control edge (Δρ), the nominal volume (QN) and the nominal pressure drop (ΔρΝ) of the control valve. 14. Stopfaggregat according to one of claims 1 to 13, characterized gegennzeichnet that the distance sensor (10) measures the Beistellweg (20). 15. Stopfaggregat according to one of claims 1 to 14, characterized in that at least two hydraulic cylinders (4, 5) are connected to a common Hydraulikzylin deransteuerventil (12), wherein between the hydraulic cylinder control valve (12) and the hydraulic cylinders (4, 5) a flow divider (31) is provided.