Railway working machine

Abstract

The invention relates to a hydraulic circuit (10) intended for installation on-board a railway working machine (1) and comprising one or more traction subcircuits (ST) having at least one variable- and / or fixed-displacement hydraulic motor (Mt) with two directions of rotation for driving one or more drive wheel sets (T, T') of the machine (1), and at least a first variable-displacement hydraulic pump (P1) with two directions of rotation for supplying power to the traction subcircuit (ST), having two inlet / outlet ports. The circuit (10) comprises at least a first hydraulic distributor (D1) capable, in a first position, of hydraulically connecting the two inlet / outlet ports of the first pump (P1) to the traction subcircuit (ST) and, in a second position, of hydraulically connecting the two inlet / outlet ports of the first pump (P1) to at least one working subcircuit (SW1) among a plurality of working subcircuits.

Description

RAILWAY WORKS MACHINE Technical field of the invention

[0001] The invention relates, in general, to the technical field of railway construction machinery. More specifically, it relates to a hydraulic circuit intended to be mounted on a railway construction machine. Prior art

[0002] Railway work machines are used to carry out installation, maintenance, repair, renewal, or dismantling work on rails, tracks, or more generally, railway installations, including infrastructure elements such as drainage systems or superstructure elements such as catenary masts, contact lines, or signaling equipment. These machines comprise one or more chassis supported by driven or non-driven wheel assemblies and equipped with track work tools.

[0003] Several operating phases of such a work machine are generally distinguished: a work phase, during which the machine's work tools are in operation while the machine travels at a low working speed, for example less than 5 km / h; an autonomous circulation phase, during which the machine is able to travel at high speed, for example more than 50 km / h, while the work tools are at rest and in a locked position; a convoy circulation phase, during which the machine is pulled by a locomotive, neither the driving wheel trains nor the work tools being powered.

[0004] The machine and its components are driven by one or more primary engines, most often internal combustion engines, as illustrated in document EP 4 019 362 A1, possibly supplemented by electric motors, as illustrated in document US 10,780,898 B2. Power transmission to the drive wheels may, at least for the autonomous operating phases, be achieved by a geared transmission kinematic chain or, where applicable, one incorporating a torque converter, as illustrated for example in document US 11,091,177 B2, or by an open or closed hydraulic circuit comprising one or more pumps driven by the primary engine(s), and one or more hydraulic motors for driving the wheel assemblies, as illustrated in document EP 4 019 362 A1.The drive systems for the driving wheelsets during operation must be adapted to the low-speed range, while ensuring a very short response time and high tracking accuracy. This sometimes necessitates the use of specific drive systems, separate from those used during autonomous operation. For example, various railway construction machines use a kinematic transmission system to drive some driving wheelsets, while others use a hydraulic circuit, as illustrated in US documents 11,091,177 B2. These drive systems can be combined in certain circumstances.

[0005] The power for work tools is most often provided by one or more dedicated hydraulic circuits, either open or closed, supplied by one or more pumps, which are themselves driven by one or more primary motors. In practice, a torque distributor is positioned at the output of a motor and drives several shafts in parallel, each driving one of the pumps. If no means of disengaging the pumps is provided, they run unloaded even when the work tools are not in operation, resulting in unnecessary energy consumption.

[0006] Thus, to operate this type of machine, several distinct systems are used, each dedicated to a specific operation: one or two systems for propelling the machine, and one or more hydraulic working circuits for driving the tools.

[0007] However, these systems are rarely used simultaneously, and they add weight to the machine. As a result, the resources used for the machine's operation are not optimized.

[0008] To address this problem, document EP 4 033 031 A1 proposes a track maintenance machine that achieves a degree of resource sharing. The track maintenance machine comprises a hydraulic circuit with a main motor and an auxiliary motor. The main motor is connected, on the one hand, to a traction sub-assembly including a gear train that mechanically drives a set of wheel assemblies for the machine; and on the other hand, to a work sub-assembly including a set of pumps connected to track maintenance tools. The auxiliary motor is connected to a power distribution gear that drives a plurality of hydraulic pumps, which are capable of supplying either some of the pumps in the work sub-assembly or the gear train in the traction sub-assembly.In certain phases of machine operation, the main motor and the axillary motor can drive separate sub-assemblies, while in other phases of operation, said motors can jointly drive either of the traction and working sub-assemblies.

[0009] However, each tool in the hydraulic circuit has its own dedicated hydraulic pump; similarly, each wheel assembly has its own dedicated motor. Consequently, the hydraulic circuit comprises numerous components, which are expensive and add weight to the system. Furthermore, each component is dedicated to a specific function, which complicates the circuit layout. Finally, the use of many components results in high energy consumption in addition to extra maintenance costs.

[0010] US patent 2013 / 0298545 describes a hydrostatic system configured for integration into an excavator. The hydrostatic system may include a first closed hydraulic circuit comprising a first hydraulic pump and a first hydraulic motor configured to actuate a first vehicle component, and a second closed hydraulic circuit comprising a second hydraulic pump and a second hydraulic motor designed to actuate a second vehicle component. In addition, a single six-port, two-position directional valve may be provided.The six-port, two-position directional valve can be configured to switch between a first and a second position such that, in the first position, the first hydraulic motor is driven by the first hydraulic pump and the second hydraulic motor is driven by the second hydraulic pump; and in the second position, the first hydraulic motor is disconnected from the first hydraulic pump and the second hydraulic motor is driven by both the first and second hydraulic pumps. US patent 2017 / 113691A1 describes a method for propelling a vehicle with a hybrid mode and a hydrostatic mode. A first transition mode is activated if the selected mode is hydrostatic and the current mode is hybrid. A target displacement for the motor-pump is defined in the first transition mode.The process may include determining the current mode (hybrid, hydrostatic, or without propulsion) and the selected mode (hybrid, hydrostatic, or without propulsion). The pump-motor displacement target can be adapted to the system consumption, and an accumulator isolation valve can be closed when the pump-motor output matches the system consumption in the first transition mode.

[0011] US patent 8,893,490B2 describes a method for controlling a hydraulic system, which includes supplying fluid to a first actuator using a first pump via a first closed-loop circuit of a machine, and supplying fluid to a second actuator using a second pump via a second closed-loop circuit of the machine. The method also includes supplying fluid to a third actuator using a third pump via a third closed-loop circuit of the machine, and supplying fluid to a fourth actuator using a fourth pump via a fourth closed-loop circuit of the machine.The method further includes the formation of a combined fluid flow comprising the fluid from the first circuit and the fluid from at least one of the second, third and fourth circuits, and the routing of the combined flow to the first actuator while supplying fluid to the actuator of at least one of the second, third and fourth circuits.

[0012] The invention aims to remedy all or part of the disadvantages of the prior art by proposing in particular a solution allowing for better allocation of the hydraulic resources of the railway work machine.

[0013] To this end, a railway work machine is proposed, comprising at least one chassis supported by at least one set of drive wheels, and at least one track work tool. The machine further comprises a hydraulic circuit. The hydraulic circuit comprises at least: a traction sub-circuit including at least one hydraulic traction motor (unidirectional or bidirectional, variable or fixed displacement) connected at least to the drive wheels of the work machine to drive one or more sets of drive wheels of the work machine; at least one first hydraulic pump with variable displacement (unidirectional and / or bidirectional), to supply the traction sub-circuit, comprising two inlet-outlet ports; and at least one first hydraulic distributor suitable, in a first position of the first hydraulic distributor.to hydraulically connect the two inlet-outlet ports of the first variable displacement hydraulic pump to the traction sub-circuit and, in a second position of the first hydraulic distributor, to hydraulically connect the two inlet-outlet ports of the first variable displacement hydraulic pump to at least one first working sub-circuit, the first working sub-circuit being a closed sub-circuit comprising one or more fixed displacement hydraulic working motors (unidirectional or bidirectional) for driving one or more track-working tools of the work machine.

[0014] Such a machine is remarkable in that the configuration of the hydraulic circuit makes it possible to limit the number of hydraulic pumps and motors in the machine, and to share their use, in order to make the machine lighter than the machines known from the state of the art.

[0015] The hydraulic circuit has the advantage of allowing both the first working sub-circuit and the traction sub-circuit to be driven by the first variable-displacement hydraulic pump. Thus, thanks to the hydraulic distributor, the first hydraulic pump is shared, meaning it is always used in the hydraulic circuit, whether the work machine is in a travel phase or a working phase.

[0016] Furthermore, the use of a variable displacement pump allows for the regulation of power transmitted to the traction and working sub-circuits. In this way, the displacement of the primary hydraulic pump can be adjusted to meet the power requirements of the working and traction sub-circuits.

[0017] In a preferred embodiment, the traction sub-circuit includes at least one variable-displacement, reversible hydraulic traction motor for adjusting the machine speed and enabling the machine to operate at low speed and high torque during vehicle start-up. Alternatively, the traction sub-circuit includes only reversible hydraulic traction motors with fixed or variable displacement.

[0018] According to one embodiment, the track work tools of the closed sub-circuit can be tamping units, brushes, track stabilizers, ballast conveyors, electric generators or even fans.

[0019] Furthermore, hydraulic actuators can be rotary or translational, unidirectional or bidirectional, for example hydraulic cylinders.

[0020] In addition, the additional hydraulic traction motors of the open sub-circuit allow the associated drive wheel set(s) to be driven during working phases, therefore at low speed, for example less than 5km / h or 3km / h, while ensuring a very short response time and high movement accuracy.

[0021] According to one embodiment, the hydraulic circuit includes at least: a second variable displacement hydraulic pump to supply the traction sub-circuit, having two inlet-outlet ports, and a second hydraulic distributor capable, in a first position of the second hydraulic distributor, of hydraulically connecting the two inlet-outlet ports of the second variable displacement pump to the traction sub-circuit and, in a second position of the second hydraulic distributor, of hydraulically connecting the two inlet-outlet ports of the second variable displacement pump to at least one second working sub-circuit among the following second working sub-circuits: an open sub-circuit comprising one or more hydraulic actuators for driving one or more track work tools and a feed pump;or an open sub-circuit comprising one or more additional fixed-displacement, double-rotating hydraulic traction motors for driving one or more drive wheelsets of the work machine and a feed pump.

[0022] Such an arrangement makes it possible to obtain a hydraulic circuit that is easily adaptable to different phases of operation of the work machine.

[0023] In the first phase of machine operation, similar to the travel phase, the first and second hydraulic distributors are in their initial position, supplying the traction sub-circuit. This allows the combined power of the first and second hydraulic pumps to drive the drive wheels, for example, during the travel phase of the construction machine. The construction machine can therefore travel at high speed.

[0024] In a second phase of machine operation, comparable to the working phase: the first and second hydraulic distributors are in the second position, and supply several working sub-circuits at the same time, which allows different jobs to be carried out simultaneously; or the first distributor is in a different position from the second distributor, one of the first and second hydraulic pumps supplying the working sub-circuit and the other the traction sub-circuit.

[0025] According to one embodiment, the second working sub-circuit includes at least the additional or variable hydraulic traction motor of a drive wheel train of the work machine.

[0026] In one embodiment, in a given state of the hydraulic circuit, the first variable displacement pump and the second variable displacement pump are connected in parallel to the traction sub-circuit. Connecting the first and second variable displacement pumps in parallel allows their power to be added together.

[0027] In one embodiment, the traction sub-circuit comprises several hydraulic traction motors for driving several drive wheel assemblies of the work machine. Preferably, to enable high-speed drive of the wheel assemblies, the hydraulic traction motors for driving several drive wheel assemblies of the work machine are connected in parallel.

[0028] In one embodiment, the circuit includes a dedicated variable-displacement hydraulic pump to supply the traction sub-circuit. Preferably, the dedicated hydraulic pump has a larger displacement than the first and second variable-displacement hydraulic pumps. Thus, the dedicated pump is used exclusively for driving the drive wheelsets. Advantageously, the dedicated variable-displacement pump and the traction circuit form a closed circuit.

[0029] According to one embodiment, the first working sub-circuit of the railway work machine includes at least one hydraulic actuator for driving a track work tool.

[0030] In one embodiment, the track work tool(s) include one or more tamping units driven by the hydraulic working motor(s). Alternatively or in addition, the track work tool(s) include at least one brush and one stabilizer. Brief description of the figures

[0031] Other features and advantages of the invention will become apparent from the following description, with reference to the attached figures, which illustrate: a schematic view of a hydraulic circuit intended to be mounted on a railway work machine, according to a first embodiment of the invention; a schematic view of the hydraulic circuit, according to a second embodiment of the invention.

[0032] For clarity, identical or similar elements are identified by identical reference symbols across all figures. Detailed description of an implementation method

[0033] Laillustre un premier mode de mise d’un circuit hydraulique10déviant à être monté sur une machine de travaux ferroviaires1.

[0034] The hydraulic circuit10 includes a set of hydraulic pumps capable of driving a set of drive sub-circuits comprising a first working sub-circuit SW1, a second working sub-circuit SW2, and a traction sub-circuit ST.

[0035] In general, the first and second working sub-circuits SW1, SW2 allow work to be carried out on the track, for example maintenance work, while the traction sub-circuit ST allows the advance of the work machine 1.

[0036] The first working sub-circuit SW1 is closed and comprises a first hydraulic motor m1 driving a first track work tool UB1, and a second hydraulic motor m2 driving a second track work tool UB2, the first and second motors m1, m2 being arranged in series. For example, as shown in the diagram, the first and second tools UB1, UB2 are track tamping units.

[0037] According to one embodiment, the first and second motors m1,m2 are one-way rotation motors with fixed displacement, the fixed displacement allowing the same power to be supplied to the first and second tools UB1,UB2, so that said tools UB1,UB2 operate at constant power, independently of the other parts of the machine 1.

[0038] Furthermore, the second working sub-circuit SW2 is an open sub-circuit comprising: a double-acting hydraulic cylinder V for driving track work tools, for example for driving track lifting and alignment clamps, lifting and lowering cylinders or clamping tamping units; an additional hydraulic traction motor mv, which is on the double direction of rotation and of fixed displacement, for driving a set of drive wheels T'' of the work machine 1.

[0039] In addition, the traction subcircuit ST comprises four hydraulic traction motors Mt, with double direction of rotation and variable displacement, two traction motors Mt being connected to a first set of driving wheels T of machine 1, and two traction motors Mt being connected to a second set of driving wheels T' of machine 1, the wheel sets T, T' of the traction subcircuit ST having a relative movement with respect to the wheel set T'' of the second working subcircuit SW2.

[0040] In particular, the displacements of the four hydraulic traction motors Mts are controllable, allowing the traction of the machine 1 to be adapted to the speed of the first and second wheel sets T, T', for example, depending on the track conditions. Thus, as required, the four hydraulic traction motors Mts are capable of operating the machine 1 at high or low speed.

[0041] The hydraulic pump assembly supplies power to the drive sub-circuits described above. More specifically, the hydraulic circuit 10 of machine 1 includes a drive motor M, preferably a combustion engine, connected to a torque distributor Rc. The torque distributor Rc distributes the power transmitted by the drive motor to the hydraulic pump assembly, and these pumps supply power to the drive sub-circuits.

[0042] According to the embodiment of the, the hydraulic pump assembly comprises a first hydraulic pump P1, a second hydraulic pump P2 and a dedicated pump PT which are mounted in parallel and are variable displacement pumps with two directions of rotation.

[0043] The dedicated pump PT continuously supplies the traction sub-circuit ST, and together with said sub-circuit PT, forms a closed traction circuit. More specifically, a portion of the power output from the drive motor M passes through the torque distributor Rce and powers the dedicated pump PT, which distributes this power to the four hydraulic motors Mt of the sub-circuit ST.

[0044] The first hydraulic pump P1 comprises two inlet-outlet ports connected to a first hydraulic distributor D1 with hydraulic and / or electrical control. The first hydraulic distributor D1 has two positions and is capable, in a first position, of connecting the two inlet-outlet ports of the first pump P1 to the traction sub-circuit ST, and in a second position, of connecting the two inlet-outlet ports of the first pump P1 to the first working sub-circuit SW1.

[0045] Thus, the use of a first hydraulic distributor D1 allows the power supplied by the first pump P1 to be directed into the traction sub-circuit ST, to allow the advance of the machine 1, or into the first working sub-circuit SW1, for the drive of the tools UB1, UB2.

[0046] Similarly, the second hydraulic pump P2 includes two inlet-outlet ports connected to a second hydraulic distributor D2 with hydraulic / electric control and two positions, the second distributor D2 allowing, in a first position, to connect the two inlet-outlet ports of the second pump P2 to the working sub-circuit ST, and, in a second position, to connect the two inlet-outlet ports of the second pump P2 to the second working sub-circuit SW2.

[0047] Furthermore, to ensure the maintenance of a minimum pressure in the second working sub-circuit SW2, which is an open sub-circuit, the torque distributor Rc is also connected to a feed pump FP of the second working sub-circuit SW2. The feed pump FP is mounted in parallel with the second hydraulic pump P2 and maintains a constant minimum pressure in the second working sub-circuit SW2 by being connected to a supply tank R of the second working sub-circuit SW2. In practice, the feed pump FP maintains a pressure greater than 10.10 5 Pa, preferably greater than 15.10 5 Pa, and less than 50.10 5 Pa, preferably less than 40.10 5 Pa, for example equal to 25.10 5Pa in the second working sub-circuit SW2. In addition, the second working sub-circuit SW2 includes a feed pressure limiter Lp, and a working pressure limiter Lp' which limit the pressure in the second working sub-circuit SW2 and a hydraulic accumulator Appermetrant to supply pressure in the second working sub-circuit SW2 to maintain it constant at all times.

[0048] Therefore, the use of the dedicated pump PT for the permanent supply of the traction sub-circuit ST, combined with the use of the first and second hydraulic distributors D1, D2 at the output of the first and second hydraulic pumps P1, P2 makes it possible to obtain different operating phases of the machine 1.

[0049] More specifically, during the machine 1's travel phase, the first and second hydraulic distributors D1, D2 are in their first position. This means that the first and second hydraulic pumps P1, P2 both supply the traction sub-circuit ST of machine 1, while the first and second working sub-circuits SW1, SW2 are not supplied. Thus, the power of the dedicated pump PT and the first and second hydraulic pumps P1, P2 combine to supply the traction sub-circuit ST. As a result, the wheel assemblies T, T' of the traction circuit PT can reach high speeds. In practice, during the travel phase, the forward speed of machine 1 can exceed 50 km / h, preferably exceeding 75 km / h; for example, it can reach 100 km / h. Furthermore, to enable machine 1 to reach such speeds, the dedicated pump PT is capable of achieving a large displacement.In particular, during the circulation phase of machine1, the displacement of the dedicated pumpPTest is greater than 50 cm³. 3 , preferably greater than 100 cm 3 For example, it can reach 250 cm 3 .

[0050] Furthermore, the ratio between the combined displacement of the dedicated pump PT and the first and second pumps P1, P2 and the displacement of the hydraulic motors M is high, which allows, for a small variation in the combined displacement of said pumps PT, P1, P2, a significant variation in the speed of machine 1. In practice and as an example, for a variation of the order of 1% of the combined displacement, the speed of machine 1 will have a speed variation of the order of 1 km / h.

[0051] During a work phase of machine 1, at least one of the first and second working sub-circuits SW1, SW2 is powered. For example, the first and second hydraulic distributors D1, D2 are in opposite positions, so that one of the first and second hydraulic pumps P1, P2 powers a working sub-circuit, and the other of the first and second hydraulic pumps P1, P2 powers the traction sub-circuit ST. In this configuration, only one working sub-circuit is in operation, and the traction sub-circuit ST is powered by two hydraulic pumps. Thus, machine 1 can perform track work operations while maintaining an average forward speed of approximately 15-20 km / h to move into position, to perform track registration before or after work, or to carry out track leveling, for example.This configuration allows, for example, the work tools UB to be brought up to temperature during a pre-work phase. This configuration is also suitable when the four traction motors Mt of the traction sub-circuit ST require significant torque, for example when the machine 1 has to move uphill.

[0052] In an alternative configuration of the machine's working phase, the first and second hydraulic distributors D1, D2 are in the second position, so that the first and second hydraulic pumps P1, P2 supply the first and second working sub-circuits SW1, SW2, and the dedicated pump PT supplies the traction sub-circuit ST. This configuration is particularly advantageous for enabling the simultaneous use of the tools of the first and second working sub-circuits SW1, SW2, in order to perform several track work operations. In this configuration, the speed of the machine is low, for example, less than 15 km / h, preferably less than 5 km / h, for example, 1 km / h.

[0053] Furthermore, the ratio between the displacement of the dedicated pump PT and the displacement of the hydraulic motors Mt of the traction sub-circuit ST is low. This means that a small variation in the displacement of the dedicated pump PT results in a small variation in the speed of machine 1. Thus, when the dedicated pump PT alone supplies the traction sub-circuit ST, the movement of machine 1 can be controlled with high precision. In practice, a variation of approximately 1% in the displacement of the dedicated pump PT will result in a speed variation of approximately 0.1 km / h.

[0054] Advantageously, to facilitate the operation of the hydraulic circuit10 during the working phase of the machine1, the first and second pumps P1 and P2 have the same displacement, which is less than the displacement of the dedicated pump PT. In practice, pumps P1 and P2 have a displacement greater than 30 cm³ 3 preferably greater than 50cm 3, for example equal to 125 cm 3 .

[0055] A second embodiment of the hydraulic circuit10 integrated into the work machine1 is illustrated. The hydraulic circuit10 comprises a set of sub-circuits including a traction sub-circuitST and a set of work sub-circuits.

[0056] The traction sub-circuit ST comprises two hydraulic traction motors Mt, here with variable displacement and double direction of rotation, driving a set of drive wheels T of the machine 1.Furthermore, the set of working sub-circuits comprises: a first closed working sub-circuit SW1 comprising two fixed-displacement, unidirectional hydraulic working motors m11, m12, each driving a tamping unit UB11, UB12 of machine 1; a second closed working sub-circuit SW2 identical to the first working sub-circuit SW1, comprising two fixed-displacement, unidirectional hydraulic working motors m21, m22, each driving a tamping unit UB21, UB22 of machine 1; a third closed working sub-circuit SW3 comprising a fixed-displacement, bidirectional hydraulic working motor m3, driving a brush B of machine 1; a fourth closed working sub-circuit SW4 comprising a fixed-displacement, bidirectional hydraulic working motor m4, driving a stabilizer S of machine 1; the first, second, third, and fourth sub-circuits of workSW1,SW2,SW3,SW4, being arranged in parallel.

[0057] The entire sub-circuit of the hydraulic circuit 1 is supplied by a set of hydraulic pumps supplied with power. According to the embodiment of the, the hydraulic circuit 10 of the machine 1 comprises a first thermal drive engine M1, and a second electric or thermal drive motor M2, said motors M1, M2 being connected to a transmission gearbox BT with two input shafts allowing the power supplied by the drive motors M1, M2 to be distributed in a torque distributor Rc of the circuit 10.

[0058] The torque distributor Rc distributes the power output from the transmission BT into the hydraulic pump assembly of the sub-circuit. In particular, the hydraulic pump assembly includes: a dedicated hydraulic pump PT with variable displacement and bidirectional rotation, continuously supplying the traction sub-circuit ST; a first hydraulic pump P1 with variable displacement and bidirectional rotation comprising two inlet-outlet ports connected to a first hydraulic distributor D1 with hydraulic and / or electrical control and two positions; a second hydraulic pump P2 with variable displacement and bidirectional rotation comprising two inlet-outlet ports connected to a second hydraulic distributor D2 with hydraulic and / or electrical control and two positions;a third hydraulic pump P3 with variable displacement and double direction of rotation comprising two inlet-outlet ports connected to a third hydraulic distributor D3 with hydraulic and / or electrical control and two positions; a fourth hydraulic pump P4 with variable displacement and double direction of rotation comprising two inlet-outlet ports connected to a fourth hydraulic distributor D4 with hydraulic and / or electrical control and two positions.

[0059] The first distributor D1 allows, in a first position, the connection of the two input-output ports of the first pump P1 to the working sub-circuit ST, and, in a second position, the connection of the two input-output ports of the first pump P1 to the first working sub-circuit SW1. Similarly, the second, third and fourth distributors D2, D3, D4 allow, in a first position, the connection of the two input-output ports of the second, third and fourth pumps P2, P3, P4 to the working sub-circuit ST, and, in a second position, the connection of said input-output ports respectively to the second, third and fourth working sub-circuits SW2, SW3, SW4.

[0060] Furthermore, the set of working sub-circuits also includes a fifth working sub-circuit SW5 open comprising: a first double-acting hydraulic cylinder V1 for driving track work tools; and a first additional hydraulic traction motor mv1 with double rotation and fixed displacement, for driving a first additional driving wheel set T1' of the work machine, the wheel set T1' having a relative movement with respect to the wheel set T of the traction sub-circuit ST; a second additional hydraulic traction motor mv2 with double rotation and variable displacement, for driving a second additional driving wheel set T2' of the work machine, the wheel set T2' having a relative movement with respect to the wheel set T of the traction sub-circuit ST and with respect to the first additional wheel set T1' of the working sub-circuit SW5;a third additional hydraulic traction motor mv3 with double direction of rotation and fixed displacement, for driving a belt conveyor C; a second double-acting hydraulic cylinder V2 for driving track work tools; a pressure limiter Lpet a hydraulic accumulator Appore to control the pressure inside the fifth working sub-circuit SW5.;

[0061] The hydraulic pump assembly here includes a fifth hydraulic pump P5 with fixed displacement and two directions of rotation. The fifth pump P5 is powered by the torque distributor Rcet and has two inlet / outlet ports. Furthermore, the fifth pump P5 is connected to a fifth hydraulic distributor D5 which, in its first position, connects the two inlet / outlet ports of the fifth pump P5 to the working sub-circuit ST, and, in its second position, connects the two inlet / outlet ports of the fifth pump P5 to the fifth working sub-circuit SW5.

[0062] The fifth working sub-circuit SW5 also includes a feed pump FP mounted in parallel with the fifth hydraulic pump P5 and connected to a supply tank R of the fifth working sub-circuit SW5, a hydraulic accumulator Apet and a working pressure limiter Lp' of the accumulator Ap.

[0063] The use of four hydraulic distributors allows the hydraulic circuit10 to have a plurality of operating phases, including a circulation phase, in which the powers of the first, second, third and fourth pumps P1, P2, P3, P4 are added with the power of the dedicated pump PT to supply the traction sub-circuit ST; and a working phase, in which at least one of the first, second, third and fourth pumps P1, P2, P3, P4 supplies one corresponding of the first, second, third and fourth working sub-circuits SW1, SW2, SW3, SW4, to carry out work operations on the tracks.

[0064] In particular, the working phase includes a plurality of hydraulic circuit configurations10 allowing the power output of the BT transmission to be distributed into one or more working sub-circuits, depending on the requirements. Furthermore, the use of variable displacement pumps arranged in parallel allows the hydraulic pump displacement to be adjusted to supply more power to the sub-circuits in use.

[0065] In general, the hydraulic circuit10 may include a dedicated pumpPT permanently connected to a traction sub-circuitST, and N hydraulic pumps with double direction of rotation and variable displacement, each of the N hydraulic pumps being able to be connected, using a corresponding distributor, either to the traction sub-circuitST or to a corresponding working sub-circuit.

[0066] Thus, in general: during the traffic phase, the N hydraulic pumps are connected to the traction sub-circuit ST to allow the vehicle to move forward at high speed; during the work phase, at least one hydraulic pump among the N hydraulic pumps is connected to a corresponding work sub-circuit to carry out work on the tracks, and the other hydraulic pumps are connected to the traction sub-circuit ST for the machine to move forward at low or medium speed.

[0067] Such a hydraulic circuit10 is easily modular to adapt to all types of track and for different repairs, and allows for better control of power distribution in the traction sub-circuitST and in the working sub-circuitsN. Furthermore, such a hydraulic circuit reduces the number of unused pumps, particularly during the running phase, and ensures that the pumps are correctly sized for the machine's needs1.

[0068] Preferably, for all embodiments, all the driving wheel assemblies of the railway work machine are hydraulically driven by one or the other of the hydraulic traction motors Mtoumv, and no mechanical transmission chain is provided between one of the thermal engines M1 or M2 and one of the driving wheel assemblies.

[0069] Naturally, the invention described above is by way of example. It is understood that a person skilled in the art is capable of carrying out different embodiments of the invention without departing from its scope.

[0070] For example, according to alternative embodiments shown in the figure, the invention may contain one or more of the following variants: the traction sub-circuit may include a variable displacement hydraulic traction motor with one direction of rotation, and a variable displacement hydraulic traction motor with two directions of rotation for driving the drive wheelset; the hydraulic circuit 10 may include more than one working sub-circuit ST for driving drive wheelsets, in particular if the machine 1 has a large number of wheelsets, for example, as illustrated in the figure, the first and second working sub-circuits SW1, SW2 may be replaced by two traction sub-circuits ST1, ST2 each comprising a fixed or variable displacement pump with two directions of rotation driving an additional wheelset or one identical to the wheelset of the traction sub-circuit ST;one and / or the other of the first and second additional drive wheel assemblies T1', T2' of the fifth working sub-circuit SW5 can be driven by two hydraulic working motors with double rotation direction and fixed or variable displacement.;

[0071] The invention may also contain embodiments not illustrated in the figures, for example: the pumps supplying the work tools may be variable or fixed displacement pumps, and unidirectional or bidirectional rotation, depending on the track work tools used; one of the working sub-circuits may include a plurality of hydraulic actuators arranged in parallel and enabling the drive of unidirectional track work tools, for example conveyors, and / or the drive of bidirectional track work tools, for example jacks; the hydraulic circuit 10 may include a thermal drive engine and an electric drive motor supplying a gearbox or a torque distributor; each drive motor, thermal or electric, may supply a single pump of the hydraulic pump assembly;One of the working sub-circuits can be continuously supplied by a hydraulic pump with one-way or two-way rotation and fixed or variable displacement, the hydraulic pump being connected to a supply tank for the working sub-circuit.

[0072] It is emphasized that all features, as they are apparent to a person skilled in the art from this description, the drawings and the attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances render such combinations impossible or meaningless.

Claims

Railway work machine (1) comprising at least one chassis supported by at least one set of driving wheels (T, T'), the railway work machine (1) further comprising a hydraulic circuit (10), the hydraulic circuit (10) comprising: at least one traction sub-circuit (ST) comprising at least one hydraulic traction motor (Mt) connected at least to the set of driving wheels (T, T') of the railway work machine (1) to drive the set of driving wheels (T, T') of the railway work machine (1), at least one first variable displacement hydraulic pump (P1) to supply the traction sub-circuit (ST), comprising two inlet-outlet ports, and at least one first hydraulic distributor (D1) capable, in a first position of the first hydraulic distributor (D1), of hydraulically connecting the two inlet-outlet ports of the first variable displacement hydraulic pump (P1) to the traction sub-circuit (ST), andin a second position of the first hydraulic distributor (D1), to hydraulically connect the two inlet-outlet ports of the first variable displacement hydraulic pump (P1) to at least one first working sub-circuit (SW1), characterized in that the first working sub-circuit (SW1) is a closed sub-circuit comprising one or more fixed displacement hydraulic working motors (m1, m2, m11, m12) driving one or more track work tools (UB1, UB2, UB11, UB12, UB21, UB22, B, S) of the railway work machine (1). Railway work machine (1) according to claim 1, characterized in that it comprises at least: a second variable displacement hydraulic pump (P2) for supplying the traction sub-circuit (ST), having two inlet-outlet ports, and a second hydraulic distributor (D2) capable, in a first position of the second hydraulic distributor (D2), of hydraulically connecting the two inlet-outlet ports of the second variable displacement pump (P2) to the traction sub-circuit (ST) and, in a second position of the second hydraulic distributor (D2), of hydraulically connecting the two inlet-outlet ports of the second variable displacement pump (P2) to at least one second working sub-circuit (SW2) among the following second working sub-circuits: an open sub-circuit comprising one or more hydraulic actuators (V) for driving one or more track work tools and a feed pump (FP);or an open sub-circuit comprising one or more additional fixed-displacement, double-rotating hydraulic traction motors (mv) for driving one or more drive wheel assemblies (T', T'') of the work machine (1) and a feed pump (FP).; Railway work machine (1) according to claim 2, characterized in that the second working sub-circuit (SW2) comprises at least the open circuit including one or more additional hydraulic traction motors (mv) with double direction of rotation and fixed displacement for driving one or more sets of driving wheels (T'') of the railway work machine (1). Railway work machine (1) according to claim 2 or claim 3, characterized in that the second working sub-circuit (SW2) comprises an open sub-circuit including one or more hydraulic actuators (V) for driving one or more track work tools and a feed pump (FP); or Railway work machine (1) according to any one of claims 2 to 4, characterized in that in a state of the hydraulic circuit (10), the first variable displacement pump (P1) and the second variable displacement pump (P2) are connected in parallel on the traction sub-circuit (ST). Railway work machine (1) according to any one of the preceding claims, characterized in that the traction subcircuit (ST) comprises several hydraulic traction motors (Mt) for driving several driving wheel trains (T, T') of the work machine (1). Railway work machine (1) according to claim 6, characterized in that the hydraulic traction motors (Mt) are connected in parallel. Railway work machine (1) according to any one of the preceding claims, characterized in that it comprises a dedicated variable displacement hydraulic pump (PT) to supply the traction sub-circuit (ST). Railway work machine (1) according to claim 8, characterized in that the dedicated variable displacement pump (PT) and the traction circuit (ST) form a closed circuit. Railway work machine (1) according to any one of the preceding claims, characterized in that the track work tool(s) driven by the fixed displacement hydraulic work motor(s) (m1, m2, m11, m12) comprise one or more tamping units (UB1, UB2, UB11, UB12).

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