Electro-hydraulic driving system and ground processing machine

Abstract

The utility model relates to an electro-hydraulic driving system which is used for a ground processing machine and is provided with at least one driving roller, and the electro-hydraulic driving system comprises at least one driving-hydraulic pump, at least one driving-hydraulic pump, at least one driving-hydraulic pump and at least one driving-hydraulic pump, at least two drive-hydraulic motors which feed hydraulic fluid by means of at least one drive-hydraulic pump; a valve device (26), wherein the valve device (26) comprises at least one switching valve unit in relation to each driving hydraulic motor; a control unit (28) for operating the valve devices (26) such that, in a base drive state, each drive-hydraulic motor for generating a drive torque is fed with hydraulic fluid by at least one drive-hydraulic pump, and, in a high-pressure drive state, each drive-hydraulic motor for generating a drive torque is fed with hydraulic fluid by at least one drive-hydraulic pump. The at least one hydraulic drive motor not used to generate the drive torque is fed with hydraulic fluid by the at least one hydraulic drive pump.

Description

Technical Field

[0001] This utility model relates to an electro-hydraulic drive system for use in ground processing machines, such as ground compactors, which has at least one drive roller. Background Technology

[0002] A ground processing machine configured as a ground compactor can include, for example, two ground processing rolls, particularly compaction rolls, arranged sequentially in the longitudinal direction of the ground compactor and rotatable about mutually parallel axes of rotation, serving as drive rolls. The two ground processing rolls, each providing a drive roll, can be driven by an electro-hydraulic drive system to rotate about their respective assigned axes of rotation. Associated with each ground processing roll, the electro-hydraulic drive system can include one or two travel-hydraulic motors that supply hydraulic fluid, either in pairs or jointly, via one or more travel-hydraulic pumps to generate drive torque. Utility Model Content

[0003] The objective of this invention is to provide an electro-hydraulic drive system for a ground processing machine, and a ground processing machine constructed using such an electro-hydraulic drive system, wherein the electro-hydraulic drive system and the ground processing machine can efficiently utilize electrical energy for driving.

[0004] According to this utility model, the above-mentioned task is solved by an electro-hydraulic drive system for a ground processing machine and having at least one drive roller, the electro-hydraulic drive system comprising:

[0005] -At least one driving-hydraulic pump, which can be driven by a drive electric motor to deliver hydraulic fluid.

[0006] - At least two travel-hydraulic motors, which are fed hydraulic fluid by means of at least one travel-hydraulic pump; - Valve assembly;

[0007] - Control unit, which operates or controls the valve device so that in the base-drive state (Grund-

[0008] In the Antriebszustand mode, each travel-hydraulic motor used to generate drive torque is fed hydraulic fluid by at least one travel-hydraulic pump, and in the high-pressure drive mode, at least one travel-hydraulic motor not used to generate drive torque is fed hydraulic fluid by at least one travel-hydraulic pump.

[0009] This invention utilizes the knowledge that increasing the pressure level of hydraulic fluid can improve the efficiency of a hydraulic drive system. To achieve this increased pressure level, the electro-hydraulic drive system constructed according to this invention is designed to deactivate or switch off a single travel-hydraulic motor that is supplied with hydraulic fluid in parallel. The pressure level of one or more travel-hydraulic motors that continue to supply hydraulic fluid to generate drive torque is also correspondingly increased, thereby enabling them to operate at higher efficiency. The higher efficiency of the travel-hydraulic motors that continue to supply hydraulic fluid to generate drive torque overcompensates for the flow losses in the travel-hydraulic motors that are deactivated or switched off without pressure.

[0010] For example, when working at a primary work point (e.g., when a ground compactor is used to compact asphalt behind an asphalt paver on a level foundation), it is possible to transition to a state where only a portion of the travel-hydraulic motors are fed hydraulic fluid to generate drive torque. In this state, essentially only one of the two compaction rollers used as drive rollers can be driven to rotate, or only one of the two travel-hydraulic motors allocated to each of the two compaction rollers can be used to generate drive torque.

[0011] To supply hydraulic fluid to different travel-hydraulic motors, it is proposed to provide at least one hydraulic circuit having at least two travel-hydraulic motors, said at least two travel-hydraulic motors being supplied with hydraulic fluid in parallel by at least one travel-hydraulic pump, and, in relation to the at least two travel-hydraulic motors in the at least one travel-hydraulic circuit, the valve device includes at least one switching valve unit.

[0012] In order to adapt the travel-hydraulic motor to various operating modes, when at least one switching-valve unit assigned to the travel-hydraulic motor switches to the basic-drive state-switching position, hydraulic fluid delivered by at least one travel-hydraulic pump can be supplied to the travel-hydraulic motor to generate drive torque. Subsequently, when at least one switching-valve unit assigned to the travel-hydraulic motor switches to the high-pressure-drive state-switching position, the hydraulic fluid supplied to the travel-hydraulic motor and flowing parallel to it... The bypass-flow path is opened, or / and, a flow short circuit is created between the two fluid connections of the travel-hydraulic motor.

[0013] In a particularly advantageous design, in order to switch the travel-hydraulic motor between working and non-working states, at least two travel-hydraulic circuits can be provided, wherein each travel-hydraulic circuit is equipped with a travel-hydraulic pump and at least two travel-hydraulic motors, which are fed hydraulic fluid in parallel by the travel-hydraulic pump.

[0014] Each travel-hydraulic pump can be assigned an electric drive motor, allowing each travel-hydraulic pump to operate independently of its assigned electric drive motor, without being related to the other travel-hydraulic pumps.

[0015] For a simple design of the valve device, the valve device in each of the travel-hydraulic circuits may include a switching valve unit associated with each travel-hydraulic motor. This switching valve unit blocks the bypass flow path parallel to the travel-hydraulic motor in the base-drive state-switching position and releases the bypass flow path in the high-pressure-drive state-switching position to allow flow.

[0016] In one alternative configuration, at least one travel-hydraulic circuit is provided in the electro-hydraulic drive system, wherein a travel-hydraulic pump and at least two (preferably at least four) travel-hydraulic motors are allocated to the at least one travel-hydraulic circuit, the travel-hydraulic motors being fed hydraulic fluid in parallel by the travel-hydraulic pump.

[0017] For the construction of an electro-hydraulic drive system having one or a single travel-hydraulic circuit, the valve device, associated with each travel-hydraulic motor, includes a switching valve unit that blocks the bypass flow path parallel to the travel-hydraulic motor in the base-drive state-switching position and releases the bypass flow path in the high-pressure-drive state-switching position to allow flow.

[0018] To achieve greater variability when activating or deactivating the travel-hydraulic motors, it is proposed that the travel-hydraulic motors form at least two travel-hydraulic motor groups fed in parallel by a travel-hydraulic pump, each having at least two travel-hydraulic motors fed in parallel by the travel-hydraulic pump, wherein, in relation to each travel-hydraulic motor group, the valve device includes at least one shut-off valve unit for selectively shutting off the travel-hydraulic motor group to prevent the supply of hydraulic fluid delivered by the travel-hydraulic pump, and releasing the travel-hydraulic motor group to supply hydraulic fluid delivered by the travel-hydraulic pump.

[0019] To achieve decoupling or coupling of the definition of a single travel-hydraulic motor-assembly, the valve device associated with each travel-hydraulic motor-assembly includes two shut-off valve units arranged on both sides of the travel-hydraulic motor-assembly along the direction of fluid flow.

[0020] In another alternative design, the valve assembly, associated with each travel-hydraulic motor, includes two switching-valve units, wherein in the base-drive state-switching position, the switching-valve unit assigned to the corresponding travel-hydraulic motor releases the hydraulic fluid supplied to the travel-hydraulic motor via the travel-hydraulic pump, and in the high-pressure-drive state-switching position, a bypass flow path parallel to the travel-hydraulic motor is released to create a flow short circuit between the fluid connections of the travel-hydraulic motor.

[0021] To enable the selective switching of one or more travel-hydraulic motors during operation, i.e., in the presence of hydraulic pressure, it is proposed to construct at least one (preferably each) switching-valve unit as a proportional valve. The availability of one or more travel-hydraulic motors during travel is particularly advantageous, especially when they can also be used (if necessary) to generate braking torque.

[0022] A further solution to the aforementioned task is a ground processing machine, preferably a ground compactor, comprising at least one drive roller and an electro-hydraulic drive system constructed according to the present invention.

[0023] Depending on the intended use of the respective ground processing machine, at least one (preferably each) drive roller may comprise a ground processing roller. Furthermore, it is conceivable that at least one drive roller comprises at least one wheel, particularly a rubber wheel.

[0024] For a method of operating a ground processing machine constructed according to the present invention, at least one of the following measures may be taken:

[0025] - Under high-pressure drive conditions, for the first part of the travel hydraulic motor, each component will be...

[0026] Matching switching - valve unit switched to high pressure - drive state - switching position,

[0027] -When transitioning from a high-pressure drive state to the braking state of the electro-hydraulic drive system, the travel-hydraulic horsepower will be...

[0028] At least a portion (preferably all) of the first part of the switching-valve unit is switched to the basic-drive state-switching position.

[0029] In order to generate sufficient driving torque under high pressure-drive conditions, it is further proposed that, in the second part of the travel-hydraulic motor, each assigned switching-valve unit is switched to the basic-drive-state switching position.

[0030] To achieve a defined, uniform load distribution, such as a load distribution on two axes or both sides of a ground machining machine, it can be configured such that the first part of the travel-hydraulic motor includes one half of the travel-hydraulic motor of the ground machining machine. The second part of the travel-hydraulic motor may include, for example, the other half of the travel-hydraulic motor of a ground processing machine.

[0031] Furthermore, the first portion of the travel-hydraulic motor can be assigned to at least one first drive roller of the ground processing machine, which is rotatable about a first rotation axis; and / or the second portion of the travel-hydraulic motor can be assigned to at least one second drive roller of the ground processing machine, which is rotatable about a second rotation axis. Thus, under high-pressure operating conditions, all active travel-hydraulic motors can act on a single axis.

[0032] For the load distribution on the two axes, a portion of the first part of the travel-hydraulic motor can be assigned to at least one first drive roller of the ground machine, which is rotatable about a first rotation axis; and a portion of the second part of the travel-hydraulic motor can be assigned to at least one first drive roller of the ground machine, which is rotatable about a first rotation axis; or / and, a portion of the first part of the travel-hydraulic motor can be assigned to at least one second drive roller of the ground machine, which is rotatable about a second rotation axis; and a portion of the second part of the travel-hydraulic motor can be assigned to at least one second drive roller of the ground machine, which is rotatable about a second rotation axis. Attached Figure Description

[0033] The present invention will be described in detail below with reference to the accompanying drawings. In the drawings:

[0034] Figure 1 This is a schematic view of a floor processing machine with two floor processing rollers, where each floor processing roller forms a drive roller;

[0035] Figure 2 Is with Figure 1 A schematic diagram of another alternative design for a ground processing machine, in which a portion of the drive roller is formed by a wheel;

[0036] Figure 3 It is a design scheme for an electro-hydraulic drive system, which is used in an electro-hydraulic drive system with two travel-hydraulic circuits;

[0037] Figure 4 It is a design scheme for an electro-hydraulic drive system, which is used in an electro-hydraulic drive system with a single travel-hydraulic circuit;

[0038] Figure 5 It is another design scheme for electro-hydraulic drive systems, which is used in electro-hydraulic drive systems with a single travel-hydraulic circuit. Detailed Implementation

[0039] Figure 1 A schematic diagram of a ground processing machine, generally designated 10 and configured, for example, as a ground compactor, is shown. This ground processing machine 10, configured as a ground compactor, includes two drive rollers 12 and 14 arranged sequentially in the longitudinal direction of the ground processing machine and respectively configured as ground processing rollers. Drive roller 12 is rotatable about a first rotation axis D1, and drive roller 14 is rotatable about a second rotation axis D2. Each of the two drive rollers 12 and 14 is assigned two travel-hydraulic motors M1, M2 or M3, M4. For example, the travel-hydraulic motors M1, M2, M3, M4 assigned to the respective drive roller 12 or 14 may be respectively disposed at their axial ends.

[0040] like Figure 1 As shown, the two drive rollers 12 and 14 can be configured as separate ground processing rollers having corresponding sections 12a, 12b and 14a, 14b. Each of these sections is assigned one of four travel-hydraulic motors M1, M2, M3, and M4, such that the two sections 12a and 12b can be driven independently of each other by their assigned travel-hydraulic motors M1 and M2, thereby rotating about the rotation axis D1, and the two sections 14a and 14b can be driven independently of each other by their assigned travel-hydraulic motors M3 and M4, thereby rotating about the rotation axis D2. However, in principle, at least one of the two drive rollers 12 and 14 can be configured as a ground processing roller that is rigid in itself and is driven to rotate at its two axial ends by its respective assigned travel-hydraulic motor.

[0041] Figure 2 Another alternative design of the ground processing machine 10 is shown, which is configured, for example, as a ground processing roller. Figure 2 The ground processing machine 10 (in its longitudinal end region) also includes a drive roller 12 configured as a ground processing roller, which has two travel-hydraulic motors M1, M2 assigned to it. In this design, the drive roller 12 is configured as a ground processing roller, which is rigid and is driven to rotate at its two axial ends by the respective assigned travel-hydraulic motors, or is capable of (e.g.) Figure 1The machine (shown) comprises two sections, which can be independently driven by respective assigned travel-hydraulic motors to rotate about the rotation axis D1. Drive rollers 16, 18, 20, and 22, respectively configured as wheels, are provided in other longitudinal end regions of the ground processing machine 10. These drive wheels can be assigned to each other, for example, in pairs, and each pair of wheels or drive rollers 16, 18 or 20, 22 can be driven to rotate by an assigned travel-hydraulic motor M3 or M4.

[0042] It should be noted that other designs of this type of floor processing machine can also be used in the electro-hydraulic drive system described below. For example, for a floor processing machine constructed as a floor compactor, a pair of drive wheels can be installed on the rear carriage, which form individual drive rollers, while the floor processing rollers on the front carriage can act as drive rollers. The principle of this invention can be applied to both pivot-supported floor processing machines or floor compactors, as well as floor processing machines divided into front and rear carriages.

[0043] exist Figure 3 In the diagram, 24 is shown as an electro-hydraulic drive system constructed according to the principles of this invention, which is used, for example, in... Figure 1 Or the ground processing machine 10 shown in Figure 2. In the design example shown, the electro-hydraulic drive system 24 includes two travel-hydraulic circuits K1 and K2. Two travel-hydraulic motors M1 and M2 can be assigned to the travel-hydraulic circuit K1, and two travel-hydraulic motors M3 and M4 can be assigned to the travel-hydraulic circuit K2.

[0044] Furthermore, a travel-hydraulic pump P1 is assigned to the travel-hydraulic circuit K1, which is driven by a separately assigned electric drive motor E1 to deliver fluid through the travel-hydraulic circuit K1 and travel-hydraulic motors M1 and M2 arranged in parallel with each other therein. Similarly, a travel-hydraulic pump P2 is assigned to the travel-hydraulic circuit K2. This travel-hydraulic pump P2 is driven by a separately assigned electric drive motor E2 to deliver fluid through the travel-hydraulic circuit K2 and travel-hydraulic motors M3 and M4, which are connected in parallel with each other and thus allow hydraulic fluid to flow.

[0045] For each of the travel-hydraulic motors M1, M2, M3, and M4, a bypass-flow path B1, B2, B3, and B4 connected in parallel is provided. For each of the four travel-hydraulic motors M1, M2, M3, and M4, the valve device of the electro-hydraulic drive system, generally indicated by 26, includes switching-valve units S1, S2, S3, and S4 arranged in each of the assigned bypass-flow paths B1, B2, B3, and B4.

[0046] Similar to the two electric drive motors E1 and E2, the switching-valve units S1, S2, S3, and S4 are also controlled by a control unit, generally indicated by 28. Through the control unit 28, the switching-valve units S1, S2, S3, and S4 can switch between a basic-drive state-switching position and a high-pressure-drive state-switching position. In the basic-drive state-switching position, which is shown in relation to each of the switching-valve units S1, S2, S3, and S4, the assigned bypass-flow paths B1, B2, B3, and B4 are blocked to prevent the flow of hydraulic fluid. This allows the hydraulic fluid supplied by the corresponding travel-hydraulic pumps P1 or P2 through the corresponding travel-hydraulic circuits K1 and K2 to flow through the two travel-hydraulic motors M1, M2, M3, and M4 respectively, and thus preferably generates the same drive torque through all four travel-hydraulic motors M1, M2, M3, and M4.

[0047] In the high-pressure drive state-switching position of the switching-valve units S1, S2, S3, and S4, the assigned bypass-flow paths B1, B2, B3, and B4 are released to allow hydraulic fluid to flow. This ensures that, as long as the assigned travel-hydraulic pumps P1 and P2 are still operating, due to lower flow resistance, the hydraulic fluid delivered by the corresponding travel-hydraulic pumps P1 and P2 is transported through the assigned travel-hydraulic motors M1, M2, M3, and M4. Furthermore, in the travel-hydraulic motors M1, M2, M3, and M4, the assigned switching-valve units S1, S2, S3, and S4 are set in the high-pressure operation state-switching position without generating drive torque. Essentially, in the high-pressure drive state of the electro-hydraulic drive system 24, or when the switching-valve units S1, S2, or S3, S4 switch to the high-pressure drive state-switching state, it is not necessary to operate the assigned travel-hydraulic pumps P1 or P2. When the travel-hydraulic pump P1 or P2 stops working, the travel-hydraulic motors M1, M2 or M3, M4 (which are driven by various assigned drive rollers that roll on the foundation) cause the liquid to tumble between the liquid joints 30, 32 that are shorted by various assigned bypass-flow paths B1, B2 or B3, B4.

[0048] It should be noted that the switching valve units S1, S2, S3, and S4 can be configured as, for example, proportional valves, so that these switching valve units can switch between their two switching positions during operation without switching surges. In simpler designs, these switching valve units S1, S2, S3, and S4 can be configured as continuous valves or dual-acting valves, capable of switching only between open and closed states. To avoid switching surges, it is preferable that such valves switch between two switching positions in a static state (i.e., under no pressure).

[0049] In, for example, a ground processing machine 10 configured as a ground compactor or in Figure 3 During normal operation of the electro-hydraulic drive system 24 shown, two travel-hydraulic pumps P1 and P2 are driven by assigned electric drive motors E1 and E2. Switching valve units S1, S2, S3, and S4 are in their base-drive state-switching position, where they block bypass flow paths B1, B2, B3, and B4 to prevent flow, thereby allowing the fluid delivered by the travel-hydraulic pumps P1 and P2 to flow through each assigned travel-hydraulic motor M1, M2, M3, and M4. Each of these travel-hydraulic motors M1, M2, M3, and M4 generates a portion of the total drive torque. For example, the two travel-hydraulic pumps P1 and P2 are configured as fixed-volume pumps. Furthermore, the travel-hydraulic motors M1, M2, M3, and M4 can be configured as fixed-volume-per-revolution motors. By controlling the electric drive motors E1 and E2 accordingly to change their speed, and thereby changing the speed or delivery volume of the travel-hydraulic pumps P1 and P2, the travel state can be changed.

[0050] If, for example, the ground processing machine 10 needs to transition to a high-pressure drive state during transport between two construction sites, the travel-hydraulic motors M3 and M4 assigned to the drive roller 14 can be deactivated. Therefore, the switching valve units S3 and S4 assigned to them are set to the high-pressure drive state-switching position, in which the switching valve units release the respective assigned bypass-flow paths B3 and B4 to allow flow. Simultaneously, the drive unit of the travel-hydraulic pump P2 can be configured so that no liquid is transported through the liquid circuit K2 via this drive unit. The travel-hydraulic motors M3 and M4 are shorted by their respective assigned bypass-flow paths, allowing them to rotate as the drive roller 14 rolls, and the liquid can be reversed through the bypass-flow paths B3 or B4 that establish the flow short circuit. Furthermore, in this state, it is also possible to further operate the travel-hydraulic pump P2 to prevent blockage of the travel-hydraulic motors M3 and M4 and thereby prevent the drive roller 14 from being dragged on the ground.

[0051] In the high-pressure drive state of the electro-hydraulic drive system 24, the entire drive torque is generated by the travel-hydraulic motors M1 and M2 of the travel-hydraulic circuit K1, which are fed by the travel-hydraulic pump P1. The higher hydraulic pressure required in the travel-hydraulic circuit K1 is generated by the correspondingly higher drive power of the electric drive motor E1. Since the hydraulic pressure operating in the travel-hydraulic circuit K1 in this state is essentially twice that in the base-drive state, the travel-hydraulic motors M1 and M2 operate with significantly higher efficiency, which is sufficient to compensate for the energy loss caused by the liquid churning caused by the linkage of the travel-hydraulic motors M3 and M4.

[0052] For example, in order to generate sufficient braking torque when going downhill, the travel-hydraulic circuit K2 of the initially undriven drive roller 14 is restarted when transitioning from the high-pressure drive state to the braking state. For this purpose, the switching valve units S3 and S4 are switched to their basic drive state switching positions, so that in the braking state, braking torque is generated by the travel-hydraulic motors M3 and M4 driven by the drive roller 14 or by the travel-hydraulic pump P1. This braking torque can also be used, for example, to feed back electrical energy through the electric drive motor E2, which operates as a generator.

[0053] exist Figure 3 The electro-hydraulic drive system 24 shown can provide various structural and operational variations. In the high-pressure drive state described above, a section of the drive roller, or if necessary, a section of the drive roller or ground processing roller that can rotate around the same axis of rotation, can be used to generate drive torque. This drive torque can also be distributed across the two drive rollers 12 and 14. For this purpose, a travel-hydraulic motor needs to be assigned to one of the two drive rollers in each travel-hydraulic circuit K1 and K2, and a travel-hydraulic motor needs to be assigned to the other drive roller. For example, travel-hydraulic motors M1 and M4 may be assigned to travel-hydraulic circuit K1, and travel-hydraulic motors M2 and M3 may be assigned to travel-hydraulic circuit K2. In the high-pressure drive state, the travel-hydraulic motor acting in relation to one of the rotating axes can generate drive torque, while the other travel-hydraulic motor assigned to the same rotating axis is linked. This arrangement is particularly advantageous when the drive rollers 12 and 14 are not separate but are constructed as rigid ground processing rollers. However, in principle, it is also possible to use drive rollers 12, 14 that are divided into multiple sections, which have a driving effect distributed in this way on sections assigned to different rotating shafts.

[0054] For example, in Figure 3 The ground processing machine 10 shown or in Figure 3In the electro-hydraulic drive system 24 shown, only one of the two travel-hydraulic circuits K1 and K2 can be switched between a basic-drive state and a high-pressure-drive state, while the other travel-hydraulic circuit is used in the high-pressure-drive state of the electro-hydraulic drive system 24 to generate drive torque. Furthermore, the travel-hydraulic circuits K1 and K2 can be configured with respect to the valve device 26 such that each of the travel-hydraulic motors M1, M2, or M3, M4 connected in parallel to each other includes only one bypass-flow path shared by them, and therefore only one separate switching-valve unit.

[0055] Figure 4 An alternative design for the electro-hydraulic drive system 24 is shown. This electro-hydraulic drive system 24 includes a separate travel-hydraulic circuit K1 with a separate travel-hydraulic pump P1 and an electric drive motor E1 assigned to it. Four travel-hydraulic motors M1, M2, M3, and M4 are divided into two groups G1 and G2. Group G1 includes travel-hydraulic motors M1 and M2, while group G2 includes travel-hydraulic motors M3 and M4. In each group G1 and G2, the travel-hydraulic motors M1 and M2 or M3 and M4 are connected in parallel to each other, and both groups G1 and G2 are fed fluid in parallel to each other via the travel-hydraulic pump P1.

[0056] Associated with each of the travel-hydraulic motors M1, M2 or M3, M4, parallel bypass-flow paths B1, B2, B3, B4 are provided, each of which carries a switching-valve unit S1, S2, S3, S4. Here, in combination with the travel-hydraulic motors M1, M2 or M3, M4 arranged in pairs as groups G1, G2, only one common bypass-flow path is provided, which carries a separate switching-valve unit.

[0057] In relation to each of the two groups G1, G2, the valve device 26 also includes two shut-off valve units V1, V2 or V3, V4. These shut-off valve units V1, V2, V3, V4, configured as proportional valves, are arranged in the flow direction on either side of their respective assigned pair of travel-hydraulic motors M1, M2 or M3, M4, and, like the switching valve units S1, S2, S3, S4, are subject to... Figure 3 The control unit 28 shown is used for control.

[0058] In the basic-drive state, the blocking-valve units V1, V2, V3, and V4 are in the state of... Figure 4The shown base-drive state-switching position releases the fluid supply to all travel hydraulic motors M1, M2, M3, and M4. Switching valve units S1, S2, S3, and S4 are also in the base-drive state-switching position, thereby closing the bypass flow paths B1, B2, B3, and B4.

[0059] If the system transitions to a high-pressure drive state and uses, for example, the travel-hydraulic motors M1 and M2 in group G1 to generate drive torque, the assigned shut-off valve units V1 and V2 and switching valve units S1 and S2 remain in the basic drive state-switching position. The shut-off valve units V3 and V4 and switching valve units S3 and S4 assigned to the travel-hydraulic motors M3 and M4 in group G2 are switched to the high-pressure drive state-switching position, where, on the one hand, the shut-off valve units V3 and V4 prevent the supply of fluid to the travel-hydraulic motors M3 and M4, and on the other hand, the bypass flow paths B3 and B4 are released by the switching valve units S3 and S4 therein to allow flow. Subsequently, the travel-hydraulic motors M3 and M4 are linked by their assigned drive rollers and are able to reverse the fluid through the respective assigned bypass flow paths B3 and B4.

[0060] Furthermore, in this design of the electro-hydraulic drive system 24, by selecting different travel-hydraulic motors M1, M2, M3, M4 and their association with the two groups G1, G2 under high pressure-drive conditions, the drive torque can be transmitted to the drive roller or to two sections of the drive roller that can rotate around the same axis of rotation, while no drive torque is generated on the other axis, or a portion of the drive torque can be generated on each of the two axes (e.g., on the segmented drive roller or in the rigid drive roller).

[0061] Another design scheme for the electro-hydraulic drive system 24 is in Figure 5 As shown in the figure. The electro-hydraulic drive system 24 also includes only a single travel-hydraulic circuit K1, which has a separate travel-hydraulic pump P1. Four travel-hydraulic motors M1, M2, M3, and M4 are connected in parallel to each other and are fed with fluid in parallel through the travel-hydraulic pump P1.

[0062] Associated with each travel-hydraulic motor M1, M2, M3, M4 or with each bypass-flow path B1, B2, B3, B4, the valve device 26 includes two switching-valve units S positioned in the flow direction on either side of each assigned travel-hydraulic motor M1, M2, M3, M4. 11 S 12 S 21 S 22 S 31 S 32 S41 S 42 .exist Figure 5 The switching-valve unit S shown 11 S 12 S 21 S 22 S 31 S 32 S 41 S 42 In the basic-drive state-switching position, the bypass-flow paths B1, B2, B3, and B4 that work together with it are blocked to prevent flow, thereby causing the liquid connectors 30 and 32 of the travel-hydraulic motors M1, M2, M3, and M4 to open to receive liquid delivered by the travel-hydraulic pump P1, or to open in the direction of the travel-hydraulic pump P1 to output liquid.

[0063] When transitioning to the high-pressure drive state, for at least one of the travel-hydraulic motors M1, M2, M3, and M4, the assigned pair of switching-valve units S 11 S 12 Or S 21 S 22 Or S 31 S 32 Or S 41 S 42 It can enter a high-pressure drive state-switching position, in which the fluid connectors 30 and 32 of the assigned travel-hydraulic motors M1, M2, M3, and M4 are disconnected from the travel-hydraulic pump P1 or the travel-hydraulic circuit K1, and connected to the assigned bypass-flow paths B1, B2, B3, and B4. Each travel-hydraulic motor M1, M2, M3, and M4, which is not used to generate drive torque in the high-pressure drive state, can reverse the fluid through the assigned bypass-flow paths B1, B2, B3, and B4.

[0064] exist Figure 5 In the design shown, any of the travel-hydraulic motors M1, M2, M3, and M4 used to generate drive torque can be used or deactivated, so that in high-pressure drive mode, for example, only one travel-hydraulic motor can be used to drive the ground processing machine 10, or three of the four travel-hydraulic motors used to generate drive torque can be used as needed.

[0065] In this design, in order to switch between different drive states during the forward movement of the ground processing machine 10, and in order to potentially activate the travel-hydraulic motor to generate braking torque in the ground processing machine 10 operating under high-pressure drive conditions, the switching-valve unit S... 11 S 12 S21 S 22 S 31 S 32 S 41 S 42 It can be configured as a proportional valve, which can achieve a gradual transition when switching between different switching states, thus avoiding switching surges.

[0066] Furthermore, it should be noted that this invention can also be applied to the electro-hydraulic drive system of a ground processing machine, which has only two travel-hydraulic motors, for example, each associated with two undivided ground processing rollers. In high-pressure drive mode, only one of the two travel-hydraulic motors can supply fluid at a correspondingly increased pressure, while fluid cannot be supplied to the other travel-hydraulic motor.

Claims

1. An electro-hydraulic drive system for a ground processing machine and having at least one drive roller, the electro-hydraulic drive system comprising: -At least one driving-hydraulic pump (P1, P2) capable of being driven by a drive electric motor (E1, E2) to deliver hydraulic fluid. - At least two travel-hydraulic motors (M1, M2, M3, M4), which are fed hydraulic fluid by means of at least one of the travel-hydraulic pumps (P1, P2), - Valve device (26), - A control unit (28) is configured to operate the valve device (26) such that, in the basic-drive state of the electro-hydraulic drive system (24), each travel-hydraulic motor (M1, M2, M3, M4) for generating drive torque is supplied with hydraulic fluid by at least one of the travel-hydraulic pumps (P1, P2), and in the high-pressure-drive state of the electro-hydraulic drive system (24), at least one travel-hydraulic motor (M1, M2, M3, M4) not for generating drive torque is supplied with hydraulic fluid by at least one of the travel-hydraulic pumps (P1, P2).

2. The electro-hydraulic drive system according to claim 1, Its features are, The system comprises at least one hydraulic circuit (K1, K2) having at least two travel-hydraulic motors (M1, M2, M3, M4), the at least two travel-hydraulic motors (M1, M2, M3, M4) being fed hydraulic fluid in parallel by at least one travel-hydraulic pump (P1, P2); and, in relation to at least two travel-hydraulic motors (M1, M2, M3, M4) in the at least one travel-hydraulic circuit (K1, K2), the valve device (26) includes at least one switching-valve unit (S1, S2, S3, S4).

3. The electro-hydraulic drive system according to claim 2, Its features are, When at least one switching-valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the base-drive state-switching position, hydraulic fluid delivered by at least one of the travel-hydraulic pumps (P1, P2) can be supplied to the travel-hydraulic motors (M1, M2, M3, M4) to generate drive torque, and subsequently, when at least one switching-valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the high-pressure-drive state-switching position, the bypass-flow path (B1, B2, B3, B4) for flow assigned to and parallel to the travel-hydraulic motors (M1, M2, M3, M4) opens or / and a flow short circuit is created between the two fluid joints (30, 32) of the travel-hydraulic motors (M1, M2, M3, M4).

4. The electro-hydraulic drive system according to claim 2, Its features are, At least two travel-hydraulic circuits (K1, K2) are provided, wherein each travel-hydraulic circuit (K1, K2) is equipped with a travel-hydraulic pump (P1, P2) and at least two travel-hydraulic motors (M1, M2, M3, M4), the travel-hydraulic motors (M1, M2, M3, M4) being fed hydraulic fluid in parallel by the travel-hydraulic pumps (P1, P2).

5. The electro-hydraulic drive system according to claim 4, Its features are, An electric drive motor (E1, E2) is assigned to each travel-hydraulic pump (P1, P2).

6. The electro-hydraulic drive system according to claim 4 or 5, Its features are, When at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the basic-drive state-switching position, hydraulic fluid delivered by at least one of the travel-hydraulic pumps (P1, P2) can be supplied to the travel-hydraulic motors (M1, M2, M3, M4) to generate drive torque, and subsequently, when at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the high-pressure-drive state-switching position, the bypass flow paths (B1, B2, B3, B4) assigned to and parallel to the travel-hydraulic motors (M1, M2, M3, M4) are opened. A flow short circuit is created between two fluid connections (30, 32) of the travel-hydraulic motors (M1, M2, M3, M4), and a valve device (26) in each of the travel-hydraulic circuits (K1, K2) includes a switching valve unit (S1, S2, S3, S4) associated with each travel-hydraulic motor (M1, M2, M3, M4), which blocks the bypass flow path (B1, B2, B3, B4) parallel to the travel-hydraulic motors (M1, M2, M3, M4) in the base-drive state-switching position and releases the bypass flow path (B1, B2, B3, B4) to allow flow in the high-pressure-drive state-switching position.

7. The electro-hydraulic drive system according to claim 2, Its features are, At least one travel-hydraulic circuit (K1) is provided, wherein a travel-hydraulic pump (P1) and at least two travel-hydraulic motors (M1, M2, M3, M4) are allocated to the at least one travel-hydraulic circuit (K1), and the travel-hydraulic motors (M1, M2, M3, M4) are fed hydraulic fluid in parallel by the travel-hydraulic pump (P1).

8. The electro-hydraulic drive system according to claim 7, Its features are, A travel-hydraulic pump (P1) and at least four travel-hydraulic motors (M1, M2, M3, M4) are assigned to the at least one travel-hydraulic circuit (K1), the travel-hydraulic motors (M1, M2, M3, M4) being fed hydraulic fluid in parallel by the travel-hydraulic pump (P1).

9. The electro-hydraulic drive system according to claim 7, Its features are, When at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the basic-drive state-switching position, hydraulic fluid delivered by at least one of the travel-hydraulic pumps (P1, P2) can be supplied to the travel-hydraulic motors (M1, M2, M3, M4) to generate drive torque, and subsequently, when at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the high-pressure-drive state-switching position, the bypass flow path (B1, ..., ...) assigned to and parallel to the travel-hydraulic motors (M1, M2, M3, M4) for flow... B2, B3, B4) open or / and create a flow short circuit between two fluid connections (30, 32) of the travel-hydraulic motors (M1, M2, M3, M4), and associated with each travel-hydraulic motor (M1, M2, M3, M4), the valve device (26) includes a switching valve unit (S1, S2, S3, S4) that blocks the bypass flow path (B1, B2, B3, B4) parallel to the travel-hydraulic motors (M1, M2, M3, M4) in the base-drive state-switching position and releases the bypass flow path (B1, B2, B3, B4) to allow flow in the high-pressure-drive state-switching position.

10. The electro-hydraulic drive system according to claim 7 or 9, Its features are, The travel-hydraulic motors (M1, M2, M3, M4) form at least two travel-hydraulic motor groups (G1, G2) fed in parallel by the travel-hydraulic pump (P1), each of the travel-hydraulic motor groups (G1, G2) having at least two travel-hydraulic motors (M1, M2, M3, M4) fed in parallel by the travel-hydraulic pump (P1), wherein, in relation to each travel-hydraulic motor group (G1, G2), the valve device (26) includes at least one shut-off valve unit (V1, V2, V3, V4) for selectively shutting off the travel-hydraulic motor groups (G1, G2) to prevent the supply of hydraulic fluid delivered by the travel-hydraulic pump (P1), and releasing the travel-hydraulic motor groups (G1, G2) to supply hydraulic fluid delivered by the travel-hydraulic pump (P1).

11. The electro-hydraulic drive system according to claim 10, Its features are, In relation to each travel-hydraulic motor-assembly (G1, G2), the valve device (26) includes two shut-off valve units (S1, S2, S3, S4) arranged on both sides of the travel-hydraulic motor-assembly (G1, G2) along the direction of fluid flow.

12. The electro-hydraulic drive system according to claim 7, Its features are, When at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4) switches to the base-drive state-switching position, hydraulic fluid delivered by at least one of the travel-hydraulic pumps (P1, P2) can be supplied to the travel-hydraulic motors (M1, M2, M3, M4) to generate drive torque, and subsequently, when at least one switching valve unit (S1, S2, S3, S4) assigned to the travel-hydraulic motors (M1, M2, M3, M4)... When S3, S4) is switched to the high-pressure-drive state-switching position, the bypass-flow paths (B1, B2, B3, B4) allocated to and parallel to the travel-hydraulic motors (M1, M2, M3, M4) for flow are opened or / and a flow short circuit is created between the two fluid joints (30, 32) of the travel-hydraulic motors (M1, M2, M3, M4), and associated with each travel-hydraulic motor (M1, M2, M3, M4), the valve device (26) includes two switching-valve units (S3, S4). 11 S 12 S 21 S 22 S 31 S 32 S 41 S 42 ), wherein, in the basic-drive state-switching position, the switching-valve unit (S) allocated to the corresponding travel-hydraulic motor (M1, M2, M3, M4) 11 S 12 S 21 S 22 S 31 S 32 S 41 S 42 The hydraulic fluid supplied by the travel-hydraulic pump (P') is released to the travel-hydraulic motors (M1, M2, M3, M4), and in the high-pressure-drive state-switching position, the bypass-flow paths (B1, B2, B3, B4) parallel to the travel-hydraulic motors are released to create a flow short circuit between the fluid connectors (30, 32) of the travel-hydraulic motors (M1, M2, M3, M4).

13. The electro-hydraulic drive system according to any one of claims 2 to 5, Its features are, At least one switching valve unit includes a proportional valve.

14. The electro-hydraulic drive system according to claim 13, Its features are, Each switching-valve unit includes a proportional valve.

15. A ground processing machine, comprising: Multiple drive rollers (12, 14; 12, 16, 18, 20, 22); And, the electro-hydraulic drive system (24) according to any one of claims 1 to 14.

16. The ground processing machine according to claim 15, Its features are, The ground processing machine is a ground compactor.

17. The ground processing machine according to claim 15, Its features are, At least one drive roller (12, 14) includes a ground processing roller; and / or at least one drive roller (16, 18, 20, 22) includes at least one wheel.

Images