Actuating device for at least one fluid power consumer

Abstract

The invention relates to an actuation device for at least one fluidically drivable load (10), such as a hydraulic actuator, consisting of at least one valve controller (V1) for controlling an alternating movement of each load (10) and at least one suspension device (14) which is connected between the valve controller (V1) and each load (10), wherein the suspension device (14) has an additional valve controller (V2), the valve piston (20) of which can be moved in a corresponding valve housing in a continuously adjustable manner. The invention is characterized in that a storage device (16) of the suspension device (14) is connected to the respective load (10) via a fluid path by means of the additional valve controller (V2) in a suspension position (V2.IV) of the valve piston (20) of the additional valve controller (V2). The invention additionally relates to a method for actuating the respective load (10) using such an actuation device.

Description

[0001] The invention relates to an actuating device for at least one fluidically driven consumer, such as a hydraulic actuator, having the features in the preamble of claim 1.

[0002] DE 10 2014 000 696 A1 discloses a device for a consumer in the form of a hydraulically controllable actuator device. The device has a working hydraulic system as a control device, via which two working chambers of the actuator device can be alternately supplied with hydraulic fluid. A valve device of the device is connected to the fluid path as part of a suspension device. In addition to a switching valve and three logic elements, this valve device has a further control device in the form of a proportional control valve.

[0003] By means of the valve device, the actuator device can be connected to a storage device as a further part of the suspension device, wherein beforehand, if the storage pressure of the storage device is higher than the working pressure in the actuator device, the storage pressure is relieved to a tank via the control valve until the working pressure is reached. During operation of the device, the switching valve serves to establish or block a fluid connection for charging the storage device. A first logic element serves to compare the working pressure with the storage pressure for the purpose of controlling a control line for controlling a second and third logic element. The second logic element serves to establish or block a fluid connection between one working chamber of the actuator device and the storage device, and the third logic element serves to establish or block a fluid connection between the other working chamber of the actuator device and the tank.If the device operates in a spring-damper mode in which the storage pressure is adapted to the working pressure, the storage device is connected to the actuator device via a fluid path through the second logic element.

[0004] US 2007 / 0056277 A1 discloses an actuating device with the features in the preamble of claim 1 for at least one fluidly drivable consumer, such as a hydraulic actuator, comprising at least one valve control device for controlling an alternating movement of the respective consumer and at least one suspension device connected between the valve control device and the respective consumer, wherein the suspension device has a further valve control device whose valve piston is continuously movable in an associated valve housing, wherein in a suspension position of the valve piston of the further valve control device, a storage device of the suspension device is connected to the respective consumer via a fluid path through the further valve control device, and wherein the valve piston of the further valve control device can be arranged in a charging position,in which the storage device is connected to a pressure supply connection for its charging via a further fluid path through the further valve control device.

[0005] Further actuating devices are disclosed in DE 10 2012 208 307 A1, DE 10 2005 054 394 A1, US 9 932 721 B2 and US 6 321 534 B1.

[0006] The invention is based on the object of providing an actuating device for at least one fluidly driven consumer which is improved in its operational reliability while having a simple structure.

[0007] This object is achieved by an actuating device according to the invention having the features of patent claim 1 in its entirety.

[0008] According to the characterizing part of claim 1, the actuating device according to the invention is characterized in that the valve piston of the further valve control device can be arranged in at least one separating position in which it separates all connections of the further valve control device from one another, and that the one separating position is provided between the suspension position and the loading position.

[0009] The disconnected position forms a standby position in which the valve piston can be arranged when a previous process step of the actuating device has been completed and the actuating device is ready for a subsequent process step. This improves the responsiveness of the actuating device.

[0010] It is further provided that in a suspension position of the valve piston of the further valve control device, a storage device of the suspension device is connected to the respective consumer via a fluid path through the further valve control device.

[0011] This allows for a simple design of the actuating device. Thus, the logic elements and the switching and control valve provided in the prior art according to DE 10 2014 000 696 A1 are obsolete or, according to the invention, replaced by the suspension device, which in its simplest embodiment has only one valve. Due to the reduced number of valves and thus also a reduced number of fluid lines and connections, the leakage of the suspension device is reduced. This is advantageous in hoist suspension systems, in which the actuating device is preferably used, because the leakage-related lowering of the hoist during operation of the hoist suspension system is reduced. This makes the actuating device more reliable.The provision of a smaller number of valves in the suspension device also improves the dynamics of the actuating device and reduces its manufacturing costs.

[0012] In a particularly preferred embodiment, the actuating device serves to adjust the fluid pressure of the accumulator pressure of the accumulator device and the load-holding suspension pressure in the consumer. It is particularly preferred that the valve control device, which is arranged in a main fluid branch, and the suspension device, which, in contrast, is arranged in a secondary fluid branch, are arranged in parallel between a pressure supply connection and the consumer. In this case, the consumer can be designed as an actuator, such as a fluid-driven motor or a fluid-driven working cylinder.

[0013] In a further preferred embodiment, it is provided that the further valve control device is designed such that, when appropriately controlled, a suspension pressure in the consumer and an accumulator pressure of the storage device gradually balance each other out and adapt to one another accordingly. It is preferably provided that the further valve control device is designed such that, when its valve piston moves into the suspension position, it at least partially establishes the fluid path in a gradually increasing manner, wherein at the same time a suspension pressure in the consumer and an accumulator pressure of the storage device balance each other out via the fluid path and accordingly gradually adapt to one another. By establishing this fluid connection, the storage device is switched on and thus the suspension is activated.If different fluid pressures prevail in the consumer and the storage device, after the initial establishment of this fluid connection, a movement of the consumer's piston rod occurs. Due to the gradual establishment of the fluid path, this movement is more controlled and gradual than a sudden movement. This allows an operator of the actuating device to intervene in and influence the movement of the piston rod. In addition, the sudden movement of the consumer's piston rod when the suspension is activated is prevented. If the actuating device for a consumer is used in the form of a working cylinder in a hoist suspension system of a mobile work machine, this can have a detrimental effect on the driving stability of the work machine and result in loss of or damage to the load lifted by the hoist.

[0014] In a further preferred embodiment, the valve piston separates the pressure supply port of the actuating device and the storage device from each other during the gradually increasing establishment of the fluid path and / or when arranged in the suspension position. This prevents a displacement of the piston rod of the consumer from occurring when the suspension is activated due to a fluid pressure at the pressure supply port that differs from the load-holding suspension pressure in the consumer.

[0015] In a further preferred embodiment, it is provided that, in order to control the further valve control device, a control device is provided for the valve piston of the further valve control device, by means of which a control side of the valve piston of the further valve control device can be subjected to a force. The control device is preferably designed as a proportional pressure regulating valve, via which a control side of the valve piston of the further valve control device can be subjected to a control fluid pressure. It is preferably provided that the proportional pressure regulating valve can be actuated electromagnetically against the force of the control fluid pressure. Alternatively, an electromotive actuator can be provided to control the valve piston of the further valve control device, which actuator acts on one control side of the valve piston of the further valve control device.As a result, only one electrical control line is required to control the suspension device, in particular the additional valve control device.

[0016] In a further preferred embodiment, it is provided that a control unit and, connected thereto, at least one input device and preferably at least one sensor device for detecting state values are provided, and that the proportional pressure control valve or the actuator can be controlled by the control unit.

[0017] The valve piston of the additional valve control device can be arranged in a charging position in which the storage device is connected to the pressure supply connection via a further fluid path through the additional valve control device for charging, and preferably the consumer is connected to this pressure supply connection via the respective valve control device. This allows the storage device to be charged with each pump pressure-increasing control command for extending or retracting the piston rod of the consumer. It is particularly preferred that an orifice or throttle, in particular an adjustable, preferably proportionally adjustable, orifice is connected to the additional fluid path.

[0018] In a further preferred embodiment, the valve piston of the further valve control device can be arranged in a discharge position, in which the storage device is connected to the tank connection via a further fluid path through the further valve control device. This allows the storage device to be emptied toward the tank, so that when the actuating device is in a resting state, no fluid pressure or energy remains trapped in the storage device. It is particularly preferred that a throttle or orifice be arranged in this fluid path.

[0019] In a further preferred embodiment, it is provided that a further separation position is provided between the loading position and the unloading position. In a further preferred embodiment, it is provided that the consumer is connected to a tank connection in the suspension position of the further valve control device, in particular via the further valve control device. Alternatively, a drain valve can be provided in a fluid connection between the consumer and the tank connection, and the control fluid pressure for actuating the drain valve can act on a control side of its valve piston.

[0020] In a further preferred embodiment, it is provided that in the fluid connection between the consumer and the further valve control device and / or between this and the storage device, a pressure sensor detects the load-holding suspension pressure or the accumulator pressure, wherein the respective pressure sensor is connected to the control unit of the actuating device for transmitting its measured pressure values. As a result, even before the connection between the storage device and the consumer is established, the accumulator pressure of the storage device can be actively and automatically adjusted to the load-holding suspension pressure of the consumer by means of the control unit, whereby movement of the consumer's piston rod when the suspension is activated is minimized or even prevented. Furthermore, the filling rate of the storage device can be adjusted based on the measured values of the pressure sensor assigned to the storage device.

[0021] In a further preferred embodiment, a load-holding valve is provided in a line connected to the consumer, which can be controlled by the proportional valve using the control fluid pressure or via an additional connection of the actuating device or by the control unit. If the load-holding valve is controlled by the control fluid pressure, separate control of the load-holding valve is unnecessary, so that the components required for such a separate control are not required. If the load-holding valve is controlled by the control unit, this can be done directly or indirectly via a pilot valve.

[0022] In a further preferred embodiment, a pressure supply source, which can be connected to the pressure supply connection, can be controlled by a load-sensing signal dependent on the accumulator pressure. This allows the pump pressure to be adjusted during a charging process of the accumulator device depending on the fluid pressure in the accumulator device.

[0023] In a further preferred embodiment, it is provided that the further valve control device is designed as a 3 / 3 or 5 / 3 or 6 / 5 proportional directional control valve in slide design.

[0024] In a further preferred embodiment, it is provided that the fluid used is hydraulic fluid, in particular hydraulic oil, so that all fluidic components of the actuating device are hydraulic components.

[0025] In a further preferred embodiment, it is provided that, in order to limit the system pressure, a further pressure control valve or a pressure shut-off valve is provided in the fluid connection between the pressure supply connection and the further valve control device and / or between this and the storage device, a pressure relief valve is provided for limiting the storage pressure.

[0026] In a further preferred embodiment, a mobile work machine, in particular a construction machine, such as a wheel loader or mobile excavator, is provided, with a lifting gear having the at least one consumer and the above-mentioned actuating device by means of which the respective consumer can be actuated.

[0027] Furthermore, the invention relates to a method for actuating at least one fluidically drivable consumer by means of an actuating device mentioned above, comprising the following method steps: charging the storage device to an initial storage pressure via the further valve control device arranged in its charging position; and moving the valve piston of the further valve control device into its suspension position, wherein the valve piston at least partially establishes the fluid path between the storage device and the consumer in a gradually increasing manner, wherein at the same time a suspension pressure in the consumer and a current storage pressure of the storage device balance each other out via the fluid path and accordingly gradually adapt to each other.By actively charging the storage device to an initial storage pressure, it is ensured that the storage device is charged at all times and is therefore ready for its spring function at all times.

[0028] In a further preferred embodiment, the initial accumulator pressure corresponds to the maximum operating pressure of the actuating device, and the adjustment of the initial accumulator pressure is carried out by discharging the accumulator device. This ensures that activation of the suspension results in a controlled and gradual extension movement of the piston rod of the consumer, which is less safety-critical than a retraction movement.

[0029] Furthermore, the fact that the accumulator device is charged to the maximum operating pressure only once before the suspension is activated, particularly in contrast to continuous accumulator pressure adjustment, can increase the energy efficiency and service life of the accumulator device and improve the response times and responsiveness of the machine.

[0030] In a particularly preferred embodiment, the suspension pressure and the accumulator pressure are detected by means of a pressure sensor, respectively. After charging the accumulator device and before connecting it to the consumer, the initial accumulator pressure is adjusted to the suspension pressure by either discharging or charging the accumulator device, depending on these detected pressures. This then corresponds to the current accumulator pressure. This minimizes or even prevents movement of the consumer's piston rod when the suspension is activated.

[0031] In a further preferred embodiment, it is provided that a damping rate is adjustable by arranging the valve piston of the further valve control device in an intermediate position between the suspension position and the adjacent separation position.

[0032] In the following, an actuating device according to the invention is explained in more detail with reference to the drawing. In a schematic representation and not to scale, the Fig. 1 to 4 each show in the form of a fluid circuit diagram a first to fourth embodiment of the actuating device according to the invention.

[0033] The figures show an actuating device according to the invention for a fluidically driven consumer 10 in the form of an actuator 10. The actuating device has a valve control device V1 for controlling an alternating movement of the actuator 10 and a suspension device 14 connected between the valve control device V1 and the actuator 10. The suspension device 14 has a storage device 16 and a further valve control device V2, the valve piston 20 of which can be continuously moved in its valve housing. The valve piston 20 of the further valve control device V2 can be arranged in a suspension position V2.V, in which it connects the storage device 16 to the actuator 10 via a fluid path through the further valve control device V2.

[0034] The actuating device is used to adjust the fluid pressure of the accumulator pressure p s the storage device 16 and the load-holding suspension pressure p a in the actuator 10 for the purpose of subsequent, in particular damped, springing of a piston rod unit 22 of the actuator 10 by means of the accumulator pressure p s the storage device 16.

[0035] The actuating device has a pressure supply source 24, which is connected with its suction side to a fluid storage tank 26 and with its high-pressure side via a fluid line to a piston-side working chamber 28 of the actuator 10. A rod-side working chamber 30 of the actuator 10 is connected to the tank 26 via another fluid line. The valve control device V1 is connected as the main control valve in the two fluid lines, which form a type of main fluid branch. Depending on the switching position of the valve V1, the high-pressure side can also be the rod side. Parallel to the valve control device V1, the suspension device 14 is connected to these two fluid lines in a type of secondary fluid branch and can be selectively switched on.

[0036] A first port V2.1 of the additional valve control device V2 of the suspension device 14 is connected via a fluid line to a branching point in the fluid line between the valve control device V1 and the piston-side working chamber 28 of the actuator 10. A second port V2.2 of the additional valve control device V2 is connected via a further fluid line to a branching point in the fluid line between the valve control device V1 and a pressure supply port P of the actuating device, to which the pressure supply source 24 is connected on the high-pressure side. A third port V2.3 of the additional valve control device V2 is connected to a fluid side of the storage device 16.

[0037] The additional valve control device V2 is designed as a proportional valve. An end position V2.V of the valve piston 20 of the additional valve control device V2 corresponds to its suspension position V2.V, in which this valve piston 20 connects the first V2.1 and the third V2.3 connection of the additional valve control device V2, separates the second connection V2.2 from all other connections of the additional valve control device V2, and connects the rod side (V2.4) to the tank (V2.5). To control the valve piston 20, one of its control sides 32 can be acted upon by a control device V5, 32 by means of a force in the direction of the one end position V2.V in the form of the suspension position V2.V, counter to the force of a compression spring 34.

[0038] The further valve control device V2 is designed in such a way that, when its valve piston 20 moves into the suspension position V2.V, it gradually creates the fluid path between the piston-side working chamber 28 of the actuator 10 and the storage device 16, whereby a load-holding suspension pressure p a in the piston-side working chamber 28 of the actuator 10 and a storage pressure p s of the storage device 16 via the fluid path and gradually adjust to each other accordingly. This pressure adjustment is considered a passive pressure adjustment. During the gradually increasing creation of this fluid path and when the valve piston 20 is arranged in the suspension position V2.V, the rod-side working chamber 30 of the actuator 10 is relieved of pressure toward the tank 26. Likewise, a gradual pressure relief of the rod-side chamber 30 takes place.

[0039] The valve piston 20 of the additional valve control device V2 can also be arranged in a charging position V2.III, in which this valve piston 20 separates the first connection V2.1 of the additional valve control device V2 from all other connections and connects its second connection V2.2 and third connection V2.3 via a fluid path. A throttle 72 or orifice can be connected into this fluid path. Between its suspension position V2.V and charging position V2.III, the valve piston 20 of the additional valve control device V2 can be arranged in a separation position V2.IV, in which it separates all connections of the additional valve control device V2 from one another.

[0040] A controllable load-holding valve V3 is connected in the fluid path between the valve control device V1 and the piston-side working chamber 28 of the actuator 10. Load-holding valve is the generic term for pipe rupture protection valves or lowering brake valves.

[0041] The actuating device also has a control unit 36. At least one input device 38 and at least one sensor device 40 for detecting status values are connected to the control unit 36. An operator of the actuating device can selectively activate or deactivate the suspension via an input device 38, 42, and can enter control commands for the actuator 10 via this or another input device 38, 44, and a damping rate of the suspension via this or another input device 38, 46. A motion sensor 48 is provided as the sensor device 40, in particular for detecting speed values.

[0042] A check valve V4 is connected in the fluid line between the branching point provided in the fluid line between the pressure supply port P and the valve control device V1, and the second port V2.2 of the further valve control device V2, which opens against the force of a compression spring in the direction of the further valve control device V2. The check valve V4 prevents the accumulator device 16 from emptying when the valve piston 20 of the further valve control device V2 is arranged in the charging position V2.III and the pressure of the pressure supply source 24 is lower than the accumulator pressure. p s is.

[0043] A first port V1.1 of the valve control device V1 is fluidly connected to the pressure supply port P via a fluid line, and a second port V1.2 is fluidly connected to the tank port T via a further fluid line. A third port V1.3 of the valve control device V1 is fluidly connected to the piston-side working chamber 28 of the actuator 10 via a further fluid line, and a fourth port V1.4 is fluidly connected to the rod-side working chamber 30 of the actuator 10 via a further fluid line. A valve piston 50 of the valve control device V1, which is designed as a 4 / 3 proportional directional control valve V1, can be moved from its unactuated first position V1.I shown in the figures against the force of a compression spring 54 into its second position V1.II, and can be moved against the force of a further compression spring 52 into its third position V1.III. The second V1.II and the third V1.III position correspond to the two end positions V1.II, V1.III of the valve piston 50. In the first position V1.I, the unactuated valve piston 50 is held by the two compression springs 52, 54 and separates all connections of the valve control device V1 from one another. Arranged in the second position V1.II, the valve piston 50 of the valve control device V1 connects its first V1.1 and its fourth V1.4 connection to one another, as well as its third V1.3 and its second V1.2 connection to one another. Arranged in the third position V1.III, the valve piston 50 of the valve control device V1 connects its first V1.1 and its third V1.3 connection to one another, as well as its fourth V1.4 and its second V1.2 connection to one another.

[0044] In the first to third embodiments according to Fig. 1 bis 3 To control the valve piston 20 of the further valve control device V2, one control side 32 of the valve piston 20 is actuated by means of a control fluid pressure against the force of the compression spring 34 p r towards one end position V2.V in the form of the suspension position V2.V. To regulate the control fluid pressure p r A proportional pressure control valve V5 is provided, whose valve piston moves against the force of the control fluid pressure p r is electromagnetically actuated. For this purpose, the control unit 36 controls a solenoid actuator 56 of the proportional pressure control valve V5.

[0045] The control fluid pressure p r is tapped at a first port V5.1 of the proportional pressure control valve and routed via a control line to a control side of the valve piston of the proportional pressure control valve V5. A second port V5.2 of the proportional pressure control valve V5 is connected to a pilot fluid pressure port C of the actuating device, and a third port V5.3 is connected to a tank line 58. Optionally, the proportional pressure control valve can be supplied from the pressure supply port P.

[0046] In addition, the control fluid pressure p r via a further control line and a control connection 60 to one control side 32 of the valve piston 20 of the further valve control device V2. To control the load holding valve V3, the control fluid pressure p r tapped at a branching point in the control line between the proportional pressure control valve V5 and the further valve control device V2 and led via a further control line to the load holding valve V3.

[0047] In the first embodiment according to Fig. 1 the additional valve control device V2 is designed as a 5 / 3-way valve. The fluid path from the rod-side working chamber 30 of the actuator 10 to the tank 26 leads via the additional valve control device V2. For this purpose, a fourth connection V2.4 of the additional valve control device V2 is connected via a fluid line to a branching point in the fluid line between the rod-side working chamber 30 of the actuator 10 and the valve control device V1. A fifth connection V2.5 of the additional valve control device V2 is connected via a fluid line to the tank line 58. In the suspension position V2.V, the fourth connection V2.4 is connected to the fifth connection V2.5, which are each separated from all other connections of the additional valve control device V2 in the charging position V2.III and the disconnecting position V2.IV.A control pressure is tapped in the tank line 58 and is led via a control line and another control connection 62 to another control side 64 of the valve piston 20 of the further valve control device V2.

[0048] In the second embodiment according to Fig. 2 The further valve control device V2 is designed as a 3 / 3-way valve. The fluid path from the rod-side working chamber 30 of the actuator 10 to the tank 26 leads via a drain valve V6, which is designed as a 2 / 2-way proportional valve V6. Fig. 2 In the uncontrolled first end position V6.I shown, a valve piston 66 of the drain valve V6 separates its two ports V6.1, V6.2 from each other, whereas these ports V6.1, V6.2 are connected to each other in its second end position V6.II. To control the drain valve V6, the control fluid pressure acts on a control side 68 of its valve piston 66. p r , which is tapped at the branching point in the control line between the proportional pressure relief valve V5 and the further valve control device V2. By means of the control fluid pressure p r the valve piston 66 of the drain valve V6 can be moved from its first V6.I to its second V6.II end position against the force of a compression spring 70.

[0049] In the first and second embodiments, the charging position V2.III of the valve piston 20 of the further valve control device V2 corresponds to its uncontrolled, other end position V2.III. In addition, in these two embodiments, the storage device 16 can be connected via a shut-off valve, and in particular via a throttle or orifice, to release the storage pressure p s or fluids can be connected to the tank 26.

[0050] In the third embodiment according to Fig. 3 The further valve control device V2 is designed as a 6 / 5-way valve. The fluid path from the rod-side working chamber 30 of the actuator 10 to the tank 26 leads via the further valve control device V2. The further valve control device V2 has a fourth V2.4 and a fifth V2.5 connection as well as another control connection 62, which, according to the first embodiment, Fig. 1 connected to components of the actuating device and are connected to or separated from one another in the suspension V2.V and separation position V2.IV of the valve piston 20. In addition, the further valve control device V2 is provided with a sixth connection V2.6, which is connected via a load reporting or load sensing connection LS and a corresponding line to the pressure supply source 24 in the form of an adjustable pump 24 for the purpose of adjusting its pressure. The LS signal could also be transmitted to the pumps via pressure transducers (at connection LS) or electronically. This would eliminate the need for the pump hose line. The pump 24 is in turn connected on the high-pressure side to the pressure supply connection P of the actuating device. When the valve piston 20 of the further valve control device V2 is arranged in its loading position V2.III, its second V2.2 and its third V2.3 ports are connected to each other via a fluid path in which a branching point is provided, to which their sixth port V2.6 is connected. The throttle 72 or orifice can be connected into the fluid path between the second port V2.2 of the further valve control device V2 and this branching point.

[0051] In the third embodiment, the valve piston 20 of the further valve control device V2 can also be arranged in a discharge position V2.I, in which its third V2.3 and fifth V2.5 connections are connected to one another via a fluid path and its remaining connections are separated from one another. A throttle 76 or orifice can be connected into this fluid path. Between its discharge V2.I and charge position V2.III, the valve piston 20 of the further valve control device V2 can be arranged in a further separation position V2.II, in which it separates all connections of the further valve control device V2 from one another. In addition, for detecting the respective fluid pressure p a , p s In the fluid line between the piston-side working chamber 28 of the actuator 10 and the further valve control device V2 as well as in the fluid line between this V2 and the storage device 16, a pressure sensor 40, 78, 80 is provided, which is connected to the control unit 36 for transmitting its measured values.

[0052] By using the pressure sensor 80 to monitor the storage pressure p s An additional pressure relief valve to safeguard the maximum storage pressure can be dispensed with, particularly after a safety assessment.

[0053] In the first to third embodiments, when the suspension is activated, in particular proportional control grooves of the respective valve piston 20 of the further valve control device V2 and / or the proportional pressure control valve V5 ensure a gradual movement of the piston rod 22 of the actuator 10. Instead of controlling the valve piston 20 of the further valve control device V2 by means of the proportional pressure control valve V5, this control can also be carried out by means of an electromotive actuator 82 according to the fourth embodiment.

[0054] In the fourth embodiment according to Fig. 4 The additional valve control device V2 is designed and connected in a manner corresponding to the additional valve control device V2 of the third exemplary embodiment. Pressure sensors 40, 78, 80 corresponding to and connected to the third exemplary embodiment are also provided. In contrast to the third exemplary embodiment, the fourth exemplary embodiment provides an electromotive actuator 82 for controlling the valve piston 20 of the additional valve control device V2, the electric motor 84 of which can be controlled by the control unit 36 via an electrical line. Furthermore, the load-holding valve V3 is controlled directly by the control unit 36.

[0055] In the third and fourth embodiments, the unloading position V2.I of the valve piston 20 of the further valve control device V2 corresponds to its uncontrolled, other end position V2.I. The loading position V2.III is provided between the unloading position V2.I and the suspension position V2.V.

[0056] The actuator 10 is designed as a working cylinder 10. The actuating device is part of a mobile work machine (not shown in the figures), in particular a construction machine, such as a wheel loader or a mobile excavator, with a lifting gear comprising the working cylinder 10. Hoist suspension systems comprising the actuating device and a lifting gear serve to increase the comfort and driving safety of the work machine.

[0057] The control unit 36 for controlling the additional valve control device V2 can correspond to the control unit 36 of the working machine. Alternatively, the control unit 36 for controlling the additional valve control device V2 can form a unit with the additional valve control device V2, which is separated from the control unit of the working machine both in terms of hardware and spatially. The latter variant has the advantage that fewer control signals are required for communication between the control unit 36 of the additional valve control device V2 and the control unit of the working machine. This allows the control unit of the working machine to be designed more simply, in that no inputs and outputs need to be provided for the suspension function.

[0058] The valve control device V1 can be provided in a main control block, and the suspension device 14, in particular the additional valve control device V2, can be provided as an attachment plate for the main control block. Alternatively, the valve control device V1 and the suspension device 14 can be designed as a monoblock.

[0059] The valve control device V1 and the further valve control device V2 can be controlled independently of one another, in particular by the control unit 36, and their valve pistons 20, 50 can be moved independently of one another accordingly.

[0060] The actuating device according to the first and second exemplary embodiments is operated as follows: Charging method step: The accumulator device 16 is charged to an initial accumulator pressure via the additional valve control device V2 arranged in its charging position V2.III. The initial accumulator pressure can correspond to the maximum operating pressure of the actuating device, which corresponds to the maximum operating pressure of the lifting gear. Because the additional valve control device V2 is connected to the pressure supply port P for supplying the actuator 10, accumulator charging can be carried out passively with each pump pressure increase controlling the actuator 10. However, the accumulator device 16 is preferably actively charged independently of any control of the actuator 10.

[0061] This can be followed by a separation process step: After charging the storage device 16, the valve piston 20 of the further valve control device V2 can be moved into the separation position V2.IV, which is provided between the charging position V2.III and the suspension position V2.V.

[0062] This is followed by a test process step: For the suspension to be activated by the control unit 36, at least one of the following requirements must be met: The suspension is activated via a corresponding input device 38, 42, in particular permanently; the suspension is not permanently deactivated via the input device 38, 42; the work machine exceeds a certain travel speed, which is detected by the speed sensor 40, 48. The control unit 36 can verify the plausibility of the activation of the suspension based on control commands for the actuator 10, which are supplied to it by the corresponding input device 38, 44. In this case, it can be provided that the suspension is only activated when the actuator 10 is not controlled by an operator via the input device 38, 44.

[0063] This is followed by the passive pressure adjustment process step: If the specified conditions are met, the load-holding valve V3 is opened to activate the suspension, provided it is in its closed position. Furthermore, the valve piston 20 of the further valve control device V2 is moved, in particular starting from its isolated position V2.IV, into its suspension position V2.V. In this process, the valve piston 20 gradually establishes the fluid path between the storage device 16 and the piston-side working chamber 28 of the actuator 10, whereby the suspension pressure p a in this working space 28 and a current storage pressure p s of the storage device 16 via the fluid path and gradually adjust to each other accordingly. At the same time, the rod-side working chamber 30 of the actuator 10 is connected to the tank 26.

[0064] The actuating device according to the third and fourth embodiments is operated as follows: In a deactivated state of the actuating device, for example when the working machine is switched off, the valve piston 20 of the further valve control device V2 is arranged in its uncontrolled discharge position V2.I, whereby the storage device 16 is relieved towards the tank 26.

[0065] Upon subsequent activation of the actuating device, for example when the working machine is switched on, the valve piston 20 can initially be moved from the unloading position V2.I into a further separation position V2.II, which is provided between the unloading position V2.I and the loading position V2.III.

[0066] This is followed by a charging process step according to the first and second embodiments, wherein the storage pressure p s monitored by the associated pressure sensor 80 and / or supplied to the pump 24 via the load-sensing line. The charging of the storage device 16 can be coordinated with the current utilization level 18 of the work machine drive unit such that the charging of the storage device 16 only occurs when the drive unit is not currently fully utilized or when sufficient power reserves are available. For this purpose, the utilization level 18 of the unit is recorded and fed to the control unit 36. The unit can be designed as an internal combustion engine or an electric motor. Depending on the storage pressure 16 and the utilization level 18 of the drive unit, a filling rate of the storage device 16 can be specified, in particular set proportionally.

[0067] The valve piston 20 can then be moved back into the separation position V2.II provided between the unloading position V2.I and the loading position V2.III.

[0068] When the suspension is activated, the test procedure step according to the first and second embodiments is carried out first, followed by the active pressure adjustment of the accumulator pressure p s to the load-holding suspension pressure p a in the piston-side working chamber 28 of the actuator 10. For this purpose, based on the measured values of the two pressure sensors 40, 78, 80, the control unit 36 determines a differential pressure between the accumulator pressure p s and the suspension pressure p a determined based on which the storage pressure p s the storage device 16 to the suspension pressure p a is actively adjusted. If the accumulator pressure is exceeded when the suspension is activated, p s higher than the suspension pressure p a is, the valve piston 20 moves into its discharge position V2.I and the accumulator device 16 is relieved towards the tank 26 until the accumulator pressure p s to the suspension pressure p a However, if the suspension pressure is adjusted when the suspension is activated p a higher than the storage pressure p s is reached, the valve piston 20 is moved to its charging position V2.III and the accumulator device 16 is charged until the accumulator pressure p s to the suspension pressure p a This is considered as active pressure adjustment. If the active pressure adjustment is carried out after the suspension has been activated due to the work machine reaching a certain travel speed and the work machine is currently accelerating under almost full load of its drive unit, it is advantageous if the storage device 16 has initially been charged to the maximum operating pressure, because then only fluid pressure p s must be drained from the storage device 16 to the tank 26, for which no power from the drive unit is required.

[0069] This is followed by the process step of passive pressure adjustment and, if necessary, the separation process step according to the first and second embodiments.

[0070] In each exemplary embodiment, the valve piston 20 assumes various intermediate positions on its travel path, in particular starting from the separation position V2.IV between the suspension position V2.V and the loading position V2.III, in the direction of its suspension position V2.V, which correspond to different damping rates of the suspension. The damping of the suspension is at its highest when the fluid connection between the storage device 16 and the actuator 10 is initially established and then decreases during the travel movement of the valve piston 20 in the direction of its suspension position V2.V. Once the valve piston 20 has finally reached its suspension position V2.V, free suspension is possible, i.e. the fluid path between the storage device 16 and the actuator 10 is essentially free of flow cross-section constrictions.Therefore, the damping rate of the suspension can be specified via the corresponding input device 38, 46 by means of a targeted arrangement of the valve piston 20 in an intermediate position between the aforementioned separation position V2.IV and suspension position V2.V.

[0071] In the first to third embodiments, the control of the valve piston 20 of the further valve control device V2 is effected from the control unit 36 via the proportional pressure relief valve V5 and in the fourth embodiment, from the control unit 36 via the electromotive actuator 82.

Claims

1. Actuating device for at least one fluidically drivable consumer (10), such as a hydraulic actuator, consisting of at least one valve control device (V1) for controlling an alternating movement of the respective consumer (10) and at least one suspension device (14) which is connected between the valve control device (V1) and the respective consumer (10), wherein the suspension device (14) has a further valve control device (V2), the valve piston (20) of which can be moved in an associated valve housing in a continuously adjustable manner, wherein, in a suspension position (V2.V) of the valve piston (20) of the further valve control device (V2), an accumulator device (16) of the suspension device (14) is connected to the respective consumer (10) via a fluid path by the further valve control device (V2), and wherein the valve piston (20) of the further valve control device (V2) can be arranged in a charging position (V2.III), in which the accumulator device (16), for charging thereof, is connected to a pressure supply port (P) via a further fluid path by the further valve control device (V2), characterised in that the valve piston (20) of the further valve control device (V2) can be arranged in at least one disconnecting position (V2.II, V2.IV) in which said valve piston disconnects all ports of the further valve control device (V2) from one other, and in that one disconnecting position (V2.IV) is provided between the suspension position (V2.V) and the charging position (V2.III).

2. Actuating device according to claim 1, characterised in that the further valve control device (V2) is configured in such a manner that, via the said control device, a suspension pressure (pa) in the consumer and an accumulator pressure (ps) of the accumulator device (16) gradually balance each other out and accordingly adjust to each other when appropriately actuated.

3. Actuating device according to either claim 1 or claim 2, characterised in that the further valve control device (V2) is configured in such a manner that, when its valve piston (20) moves into the suspension position (V2.V), it establishes the fluid path at least partially in a gradually increasing manner, wherein the suspension pressure (pa) in the consumer (10) and the accumulator pressure (ps) of the accumulator device (16) simultaneously balance each other out via the fluid path and accordingly adjust to each other in a gradually increasing manner.

4. Actuating device according to any of the preceding claims, characterised in that the valve piston (20) disconnects the pressure supply port (P) of the actuating device and the accumulator device (16) as the fluid path is established in a gradually increasing manner and / or when it is arranged in the suspension position (V2.V).

5. Actuating device according to any of the preceding claims, characterised in that, to actuate the further valve control device (V2), a proportional pressure-regulating valve (V5) is provided via which a control fluid pressure (pr) can be applied to a control side (32) of the valve piston (20) of the further valve control device (V2).

6. Actuating device according to claim 5, characterised in that the proportional pressure-regulating valve (V5) can be electromagnetically actuated against the force of the control fluid pressure (pr).

7. Actuating device according to any of the preceding claims, characterised in that a further disconnecting position (V2.II) is provided between the charging position (V2.III) and a discharging position (V2.I) of the valve piston (20) of the further valve control device (V2), in which the accumulator device (16) is connected to a tank port (T) via the further valve control device (V2).

8. Actuating device according to any of the preceding claims, characterised in that a discharge valve (V6) is provided in a fluid connection between the consumer (10) and the tank port (T) and in that, to actuate the discharge valve (V6), the control fluid pressure (pr) acts on a control side (68) of its valve piston (66).

9. Actuating device according to any of the preceding claims, characterised in that a pressure sensor (40, 78), which detects the suspension pressure (pa) of the consumer (10), and preferably a further pressure sensor (40, 80), which detects the accumulator pressure (ps) of the accumulator device (16), is provided, each of which is connected to a control unit (36) of the actuating device for transmitting its pressure measurement values.

10. Actuating device according to any of claims 5 to 9, characterised in that a load-holding valve (V3) is provided which safeguards the suspension pressure (pa) in the consumer (10) and can be controlled by the proportional pressure-regulating valve (V5) by means of the control fluid pressure (pr) or via an additional port of the actuating device or by the control unit (36).

11. Method for actuating at least one fluidically drivable consumer (10) by means of an actuating device according to any of claims 1 to 10, having the following method steps: - charging the accumulator device (16) to an initial accumulator pressure via the further valve control device (V2) arranged in its charging position (V2.III); and - moving the valve piston (20) of the further valve control device (V2) into its suspension position (V2.V), wherein the valve piston (20) establishes the fluid path between the accumulator device (16) and the consumer (10) at least partially in a gradually increasing manner, wherein a suspension pressure (pa) in the consumer (10) and a current accumulator pressure (ps) of the accumulator device (16) simultaneously balance each other out via the fluid path and accordingly adjust to each other in a gradually increasing manner.

12. Method according to claim 11, characterised in that the suspension pressure (pa) and the accumulator pressure (ps) are each detected by means of a pressure sensor (40, 78, 80) and in that, after the accumulator device (16) has been charged to the initial accumulator pressure and before it is connected to the consumer (16), the initial accumulator pressure is adjusted to the suspension pressure (pa) as a function of these detected pressures (pa,ps) by either discharging or charging the accumulator device (16).

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