Operating device for at least one fluid-driven load

Abstract

An operating device for at least one fluid-operable load 10, such as a hydraulic actuator, is disclosed, which comprises at least one valve control device V1 for controlling the alternating movement of the respective load 10 and at least one spring suspension device 14, said spring suspension device being connected between said valve control device V1 and said respective load 10, said spring suspension device 14 having another valve control device V2, the valve piston 20 of which is infinitely movable in an associated valve housing, characterized in that in a spring suspension position V2.IV of the valve piston 20 of said other valve control device V2, the storage device 16 of said spring suspension device 14 is connected to said respective load 10 by said other valve control device V2 via a fluid path.

Description

[Technical field]

[0001] The invention relates to an actuating device for at least one fluid-driven load, such as a hydraulic actuator, which comprises at least one valve control device for controlling the alternating movement of the respective load and at least one spring suspension device connected between the valve control device and the respective load, the spring suspension device having a further valve control device, the valve piston of which is infinitely movable in an associated valve housing. [Background technology]

[0002] From DE 10 2014 000 696 A1 a device for a load in the form of a hydraulically actuable actuator device is known, which has as a control device a working hydraulic device via which hydraulic fluid can be selectively supplied to two working chambers of the actuator device. A valve device of the device is connected to this fluid path as part of a spring suspension device, which valve device has, besides a changeover valve and three logic elements, 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 another part of the spring suspension device, and if the storage pressure of the storage device is higher than the working pressure in the actuator device, the storage pressure is previously unloaded via the control valve towards the tank until the working pressure is reached. During operation of the device, the changeover valve is used to make or block a fluid connection for filling the storage device. A first logic element is used to compare the working pressure with the storage pressure in order to drive a control line for driving the second and third logic elements. A second logic element is used to make or block a fluid connection between one working chamber of the actuator device and the storage device, and a third logic element is used to make or block a fluid connection between the other working chamber of the actuator device and the tank. When the device works 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 by the second logic element via a fluid path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE 102014000696 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide an actuating device for at least one fluid-drivable load, which has a simple construction and an improved drive safety. [Means for solving the problem]

[0006] This problem is solved by an operating device according to the invention, which has as a whole the features of patent claim 1.

[0007] According to the characterizing part of claim 1, the operating device according to the invention is characterized in that in the spring-suspended position of the valve piston of the further valve control device, the storage device of the spring-suspended device is connected to the respective load via a fluid line by the further valve control device.

[0008] The actuating device can thus be constructed in a simple manner, i.e. the logic elements and the switching and control valves provided in the prior art according to DE 10 2014 000 696 A1 are dispensed with or are replaced according to the invention by a spring suspension, which in the simplest embodiment only has one valve. Despite the reduced number of valves and thus the reduced number of fluid lines and fluid connections, the actuating device still has a high operating safety. The provision of a smaller number of valves in the spring suspension further improves the dynamics of the actuating device and reduces the costs involved in its construction.

[0009] In a particularly preferred embodiment, the actuating device is used for hydraulic adaptation of the spring suspension pressure, including the storage pressure in the storage device and the load in the load, where the load can be configured as an actuator, for example as a hydraulically driven engine or as a hydraulically driven working cylinder.

[0010] In another preferred embodiment, a closed-loop control unit is provided and the further valve control is arranged so that, when the closed-loop control unit is used to drive the valve control unit, the spring suspension pressure in the load and the storage pressure in the storage device are gradually compensated for each other and appropriately adapted to each other via the valve control unit. With this gradual pressure compensation, the piston rod of the load performs a slow and controlled travel movement. By virtue of this movement, which is rather slow as opposed to a jump movement, the user of the operating device has the possibility to intervene in the movement process of the piston rod and adjust it. Furthermore, a jump movement of the piston rod of the load is prevented when the spring suspension is activated, which, if the operating device is used for a load in the form of a working cylinder of a spring suspension system of a lifting device of a mobile working machine, can have a negative effect on the driving stability of the working machine and can result in the loss and damage of the load lifted by the lifting device.

[0011] Preferably, the valve piston can be arranged in a pressure compensation position, in which it connects the storage device and the load via a fluid line, in which a flow cross-sectional narrowing device is provided, which at least partially realizes a gradual pressure compensation. Alternatively and / or additionally, the further valve control device can be arranged in such a way that, when its valve piston moves, in particular from the disconnected position to the pressure compensation position, it at least partially forms a gradually enlarging fluid line, at the same time the spring suspension pressure in the load and the storage pressure of the storage device are mutually compensated and correspondingly match each other in a gradually increasing manner. By forming such a fluid connection, the storage device is connected. After the formation of this fluid connection, a movement of the piston rod of the load is brought about, in the case where different pressures prevail in the load and in the storage device. In particular due to the gradually increasing formation of the fluid line, the movement of the piston rod of the load is managed and takes place gradually. In particular a proportional control groove of the valve piston of the further valve control device ensures a gradual running movement of the piston rod of the actuator.

[0012] Preferably, when the valve piston of the other valve control device is arranged in a spring-loaded position and / or a buffered position, the working chamber on the rod side of the actuator can, if necessary, be unloaded by the other valve control device via a fluid path towards the tank connection end.

[0013] In another preferred embodiment, at least one sensor device is provided for detecting state values ​​of the drive and actuating devices for the valve piston of the further valve control device, which are connected to the closed-loop control unit. Particularly preferably, in the fluid connection between the load and the further valve control device and / or between the further valve control device and the storage device, a pressure sensor detects the fluid pressure, which pressure sensor is connected to the closed-loop control unit for transmitting the pressure measurement value. This allows a pressure difference to be determined permanently by the closed-loop control unit, on the basis of which the valve piston of the further valve control device can be driven, in particular for pressure matching between the storage device and the load.

[0014] In another preferred embodiment, the drive for the valve piston of the further valve control device is designed as an electric actuating drive which acts on the control side of this valve piston, so that only an electric control line needs to be provided, in particular for actuating the spring suspension of the further valve control device.

[0015] In another preferred embodiment, the fluid used is a hydraulic fluid, in particular a hydraulic oil, so that all fluid components of the operating device are hydraulic components.

[0016] The subject of the invention is also a mobile work machine, such as, for example, a construction machine, a wheel loader or a mobile excavator, having a lifting device or an axle spring suspension with at least one load and an operating device as described above with which the respective load can be operated.

[0017] The operating device according to the invention is explained in more detail below with the aid of the drawings, which are shown in principle and in a non-to-scale representation in a single figure. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 shows an operating device according to the invention in a principle and not to scale representation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The operating device comprises a valve control device V1 for controlling the alternating movement of the actuator 10 and a spring suspension device 14, which is connected between the valve control device V1 and the actuator 10. The spring suspension device 14 comprises a storage device 16 and a further valve control device V2, the valve piston 20 of which is infinitely movable in its valve housing. The valve piston 20 of the further valve control device V2 can be positioned in a spring suspension position V2.IV, in which it connects the storage device 16 by means of the further valve control device V2 with the actuator 10 via a fluid path.

[0020] The operating device is used for hydraulically matching the storage pressure ps of the storage device 16 with the spring pressure pa including the load in the actuator 10 for subsequent, in particular damped, spring suspension of the piston rod unit 22 of the actuator 10 by the storage pressure ps of the storage device 16.

[0021] The actuation device has a pressure supply connection P, which is connected via a fluid line to a working chamber 28 on the piston side of the actuator 10. A working chamber 30 on the rod side of the actuator 10 is connected via another fluid line to a tank connection T. A valve control device V1 is connected in the two fluid lines as a main control valve. Depending on the respective switching position of the valve V1, the above-mentioned connections can also be reversed.

[0022] The first connection end V2.1 of the other valve control device V2 of the spring suspension 14 and its second connection end V2.2 are connected in a fluid-guiding manner to a branch point which is connected via a fluid conduit to the fluid conduit between the valve control device V1 and the working chamber 28 on the piston side of the actuator 10. The third connection end V2.3 of the other valve control device V2 is connected via another fluid conduit to the fluid conduit between the valve control device V1 and the working chamber on the rod side of the actuator 10. The fourth connection end V2.4 of the other valve control device V2 and its fifth valve connection end V2.5 are connected in a fluid-guiding manner to a branch point which is connected via a fluid conduit to the fluid side of the storage device 16. The sixth connection end V2.6 of the other valve control device V2 is connected to the tank conduit 58.

[0023] The other valve control device V2 is configured as a proportional valve. The end position V2.IV of the valve piston 20 of the other valve control device V2 corresponds to its spring-suspended position V2.IV. In the spring-suspended position V2.IV, the valve piston 20 connects the first connection end V2.1 with the fourth connection end V2.4, the second connection end V2.2 with the fifth connection end V2.5 and the third connection end V2.3 with the sixth connection end V2.6 via fluid paths, which preferably do not each have a flow cross-sectional constriction device. To drive the valve piston 20, a force can be applied to one of its control sides 32 by a drive device 82 against the force of a compression spring 34 in the direction of the end position V2.IV in the form of the spring-suspended position V2.IV.

[0024] A pressure sensor 40, 78 is provided for detecting the fluid pressure pa at a branch point, which is connected to a first connection end V2.1 and a second valve connection end V2.2 of the second valve control device V2. Another pressure sensor 40, 80 is provided for detecting the fluid pressure ps in the fluid conduit between the branch point, which is connected to the fourth and fifth connection ends V2.5 of the other valve control device V2, and the storage device 16. Each pressure sensor 40, 78, 80 is connected to the closed-loop control unit 36 ​​of the operating device for transmitting its measured values.

[0025] Using the measured values ​​of the pressure sensors 40, 78, 80, the pressure difference is permanently determined by the closed-loop control unit 36, based on which the valve piston 20 of the other valve control device V2 is driven by the closed-loop control unit 36, in particular to pressure match the storage pressure ps of the storage device 16 with the spring pressure pa in the working chamber 28 on the piston side of the actuator 10.

[0026] The drive device 82 is configured as an electric actuating drive 82, the electric motor 84 of which can be driven by the closed-loop control unit 36 ​​via an electrical conductor and which actuating drive acts on the control side 32 of the valve piston 20 of the further valve control device V2 using an actuating force.

[0027] The valve piston 20 of the further valve control device V2 can be arranged in a pressure compensation position V2.II, in which the second connection end V2.2 and the fifth connection end V2.5 are connected to one another via a fluid line into which a flow cross-section narrowing device 42 in the form of a throttle 42 or a baffle 42 is connected, which is used in the pressure compensation position V2.II to throttle the fluid flow between the second connection end V2.2 and the fifth connection end V2.5 of the further valve control device V2, so that a gradual pressure compensation is achieved between the storage device 16 and the actuator 10. All other connection ends of the further valve control device V2 are separated from one another in the pressure compensation position V2.II of the valve piston 20.

[0028] The valve piston 20 of the further valve control device V2 has a buffer position V2.III between the spring-suspended position V2.IV and the pressure-compensated position V2.II. In the buffer position V2.III, the first connection end V2.1 of the further valve control device V2 is connected to its fourth connection end V2.IV, its second connection end V2.2 to its fifth connection end V2.5 and its third connection end V2.3 to its sixth connection end V2.6 via fluid paths in which flow cross-section narrowing devices 44 in the form of throttles 44 or baffles 44 are connected respectively. In the buffer position V2.III, the flow cross-section narrowing devices 44 are used to throttle the fluid flow through the respective fluid paths, whereby a buffered spring suspension can be achieved.

[0029] When not actuated, the valve piston 20 of the further valve control device V2 is located in its further end position V2.I, which corresponds to the disengagement position V2.I of the valve piston 20, in which position the valve piston disengages all connection ends of the further valve control device V2 from one another.

[0030] A pressure limiting valve V3 for limiting the maximum storage pressure Ps is connected to the fluid line between the branch point, which is connected to the fourth and fifth connections V2.4 and V2.5 of the further valve control device V2, with its inlet connection V3.1 and its outlet connection V3.2 leading into the tank line 58. The storage pressure is preferably limited to a maximum of 280 bar. A control fluid pressure acts on the control side of the pressure limiting valve V3, which is tapped off at its inlet connection V3.1 and guided to this control side via a control line. With the control fluid pressure, a valve piston of the pressure limiting valve V3 can be operated against the force of an adjustable compression spring. A further pressure limiting valve V4 is connected with its inlet connection V4.1 to limit the maximum system pressure, in particular the fluid pressure of the actuating device, to the branch point connected to the first connection V2.1 and the second connection V2.2 of the further valve control device V2 and with its outlet connection V4.2 to the tank line 58. The system pressure is preferably limited to a maximum of 420 bar. This further pressure limiting valve V4 is designed similarly to the pressure limiting valve V3. An additional intake valve (not shown), for example in the form of a spring-loaded check valve, can be connected in parallel to the valve V4 in the lowest connecting line shown in the figure.

[0031] A shutoff valve V5 is arranged in parallel to the pressure limiting valve V3. One connection end V5.1 of this shutoff valve V5 is connected to a fluid line which connects the fluid line connected to the storage device 16 with the pressure limiting valve V3. The other connection end V5.2 of the shutoff valve V5 is connected to the tank line 58. The shutoff valve V5 is arranged in its blocking position during operation of the operating device and can be moved to its open position in order to discharge the storage pressure ps from the storage device 16, for example for maintenance work. A non-return valve V6 is connected in the fluid line between the branch point connected to the first connection end V2.1 and the second connection end V2.2 of the other valve control device V2 and the other pressure limiting valve V4. A further non-return valve V6 is connected in the fluid line connecting the fluid line connected to the third connection end V2.3 of the other valve control device V2 with the other pressure limiting valve V4. The two non-return valves each open in the direction of the other pressure limiting valve V4 against the force of a compression spring.

[0032] The first connection V1.1 of the valve control device V1 is connected in a fluid-conducting manner to the pressure supply connection P, and the second connection V1.2 to the tank connection T. The third connection V1.3 of the valve control device V1 is connected via another fluid line to the piston-side working chamber 28 of the actuator 10, and the fourth connection V1.4 is connected via another fluid line to the rod-side working chamber 30 of the actuator 10. The valve control device V1 is configured as a 4 / 3 proportional-route valve V1. The valve piston 50 of the valve control device V1 can be moved from the first non-operated position V1.I shown in the figure to its second position V1.II against the force of a compression spring 52 by means of a magnetic actuator 56 and can be moved to its third position V1.III against the force of another compression spring 54 by means of another magnetic actuator 57. Instead of magnetic actuation, other types of actuation can also be selected.

[0033] The second position V1.II and the third position V1.III 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 two compression springs 52, 54 and connects the second connection end V1.2 with the third connection end V1.3 and the fourth connection end V31.4 of the valve control device V1 to one another, whereas its first connection end V1.1 is separated from all other connection ends. Arranged in the second position V1.II, the valve piston 50 of the valve control device V1 connects its first connection end V1.1 with its fourth connection end V1.4 to one another and its third connection end V1.3 with the second connection end V1.2 to one another. Being arranged in the third position V1.III, the valve piston 50 of the valve control device V1 connects its first connection end V1.1 and its third connection end V1.3 to each other and its fourth connection end V1.4 and its second connection end V31.2 to each other.

[0034] The valve control device V1 and the further valve control device V2 can be driven independently of one another, in particular by the closed-loop control unit 36, and their valve pistons 20, 50 can likewise move independently of one another.

[0035] The actuator 10 is configured as a working cylinder 10. The operating device is part of a mobile work machine, in particular a construction machine, such as a wheel loader or a mobile excavator, which has a lifting device or an axle spring suspension with the working cylinder 10, not shown in the figures. The lifting device spring suspension system with the operating device and the lifting device is used to increase the comfort and driving safety of the work machine. Instead of a lifting device, an axle spring suspension is also conceivable.

[0036] The closed-loop control unit 36 ​​is equipped with software by means of which it is possible, preferably according to the measured values ​​of the pressure sensors 40, 78, 80, to drive the actuating devices, in particular the drives 82, 56, 57 of the valve control devices V1, V2, in such a way that the actuating devices perform the following functions: - free, and therefore flow-restriction-free, spring suspension of the piston rod unit 22 of the actuator 10 by placing the valve piston 20 of the other valve operating device V2 in the spring-suspended position V2.IV; and / or - damped spring suspension of the piston rod unit 22 of the actuator 10 by placing the valve piston 20 of the other valve control device V2 in the damped position V2.III; and / or pressure compensation of the storage pressure ps of the storage device 16 and the spring suspension pressure pa with the load in the working chamber 28 on the piston side of the actuator 10, possibly during the process of raising or lowering the lifting device of the working machine, by placing the valve piston 20 of the further valve control device V2 in the pressure compensation position V2.II; and / or - maintaining a minimum storage pressure (ps) in the storage device 16 according to the measurements of the pressure sensors 40, 78, 80, in particular when the valve piston 20 of the other valve control device V2 is arranged in the disconnection position V2.I, which must not fall below, since the reactivity of the system depends on this; and / or - by placing the valve piston 20 of the other valve control device V2 in the disconnected position V2.I, possibly when the lifting device is in the working mode, deactivation of the spring suspension and no pressure compensation; and / or - monitoring the maximum storage pressure (ps) in the storage device 16, in particular when the valve piston 20 of the further valve control device V2 is arranged in the pressure compensation position V2.II, the buffer position V2.III or the spring-suspended position V2.IV.

[0037] The advantage of this software solution is that it can be retrofitted to existing systems.

Claims

1. 1. An operating device for at least one fluid-actuable load (10), such as a hydraulic actuator, comprising at least one valve control device (V1) for controlling the alternating movement of the respective load (10) and at least one spring suspension device (14), said spring suspension device being connected between said valve control device (V1) and said respective load (10), said spring suspension device (14) having another valve control device (V2), the valve piston (20) of which is infinitely movable in an associated valve housing, an operating device characterized in that in the spring-suspended position (V2.IV) of the valve piston (20) of the other valve control device (V2), the storage device (16) of the spring-suspended device (14) is connected to the respective load (10) by the other valve control device (V2) via a fluid path.

2. 2. The actuating device according to claim 1, characterized in that a closed-loop control unit (36) is provided and the further valve control device (V2) is arranged in such a way that, when driven accordingly by the closed-loop control unit (36), the spring suspension pressure (pa) in the load and the storage pressure (ps) in the storage device (16) are gradually mutually compensated for and accordingly adapted to one another via the valve control device.

3. 2. The actuating device according to claim 1, characterized in that the valve piston (20) can be arranged in a pressure compensation position (V2.II), in which the valve piston (20) connects the storage device (16) and the load (10) by means of the further valve control device (V2) via another fluid line, in which a flow cross-section constriction device (42) is provided, which at least partially realizes gradual pressure compensation.

4. 3. The operating device according to claim 2, further comprising a drive device for the valve piston of the other valve control device and at least one sensor device for detecting state values ​​of the operating device, the drive device and the operating device being connected to the closed-loop control unit.

5. 3. The operating device according to claim 2, characterized in that a pressure sensor (40, 78) for detecting the spring suspension pressure (pa) of the load (10) and / or a further pressure sensor (40, 80) for detecting the storage pressure (ps) of the storage device (16) are provided, each of the pressure sensors being connected to the closed-loop control unit (36) for transmitting its pressure measurement value.

6. 5. The actuating device according to claim 4, wherein the drive (82) for the valve piston (20) of the further valve control device (V2) is configured as an electrically actuated drive, which acts on the control side (32) of this valve piston (20).

7. 2. The actuation device according to claim 1, characterized in that the valve piston (20) of the further valve control device (V2) can be arranged in a buffer position (V2.III), in which position the storage device (16) is connected to the respective load (10) by the further valve control device (V2) via at least one further fluid line, in which a flow cross-section restriction device (44) is respectively connected.

8. 2. The operating device according to claim 1, wherein the valve piston (20) of the other valve control device (V2) can be positioned in a disconnection position (V2.I), in which position the valve piston disconnects all connection ends of the other valve control device (V2) from each other.

9. 2. The operating device according to claim 1, characterized in that a pressure limiting valve (V3) is provided to limit the maximum storage pressure (Ps) of the storage device (16) and / or a further pressure limiting valve (V4) to limit the maximum fluid pressure of the operating device.

10. 2. The operating device according to claim 1, characterized in that the further valve control device (V2) is formed as a 6 / 4 proportional root valve of slider construction.

11. A mobile working machine having a lifting device or axle spring suspension with at least one load (10), A travelable work machine provided with an operating device according to any one of claims 1 to 10, wherein each load (10) can be operated using the operating device.

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