Electrohydraulic System Having an Adjustment Device for a Valve

Abstract

An electrohydraulic system having an adjustment device for a valve includes a drive apparatus, a control apparatus, and a preloading apparatus. In the event of a fault, the energy stored in the preloading apparatus can be transferred to the control apparatus such that a rotational motion of the control apparatus begins, which leads to the adjustment of the valve. The preloading apparatus comprises at least one elastic element, which is arranged adjacent to a control shaft of the control apparatus, is stationarily connected to the control shaft, and applies a torque to the control shaft.

Claims

1. An electrohydraulic system comprising: an adjustment device for a valve, the adjustment device comprising: a drive; an actuating arrangement having an actuating shaft; and a pretensioning device configured to transmit energy stored in the pretensioning device to the actuating arrangement in the event of a fault such that rotational movement of the actuating arrangement is initiated so as to cause the valve to be adjusted, the pretensioning device including at least one elastic element arranged adjacent to the actuating shaft of the actuating arrangement and connected fixedly to the actuating shaft, the at least one elastic element being configured to exert a torque on the actuating shaft.

2. The electrohydraulic system as claimed in claim 1, wherein the elastic element comprises at least one spring system with at least one pretensioning spring.

3. The electrohydraulic system as claimed in claim 2, further comprising at least one lever arm attached to the actuating shaft and having a first end at which the at least one pretensioning spring engages.

4. The electrohydraulic system as claimed in claim 2, wherein a direction of action of the at least one pretensioning spring extends essentially parallel to a tangent to the actuating shaft.

5. The electrohydraulic system as claimed in claim 1, wherein the pretensioning device is pretensioned by at least one rotatable electromotor.

6. The electrohydraulic system as claimed in claim 1, wherein the pretensioning device is pretensioned by at least one hydraulic cylinder having at least one linearly movable pressure piston.

7. The electrohydraulic system as claimed in claim 6, wherein the hydraulic cylinder is connected via at least one duct to at least one directional control valve and, when the at least one directional control valve opens, the pressure piston of the hydraulic cylinder is displaceable by the pretensioning device.

8. The electrohydraulic system as claimed in claim 1, wherein the actuating shaft of the actuating arrangement and a drive axis of the valve are arranged coaxially with each other.

9. The electrohydraulic system as claimed in claim 1, further comprising a tensioning device configured to tension the pretensioning device.

10. The electrohydraulic system as claimed in claim 1, further comprising a triggering mechanism for the pretensioning device.

11. The electrohydraulic system as claimed in claim 1, further comprising a resetting mechanism for the pretensioning device.

Description

[0033] The invention and the technical environment will be explained in detail below with the aid of drawings. The same components are designated here with the same reference symbols. The views are provided schematically and not to illustrate size ratios. The explanations given with reference to individual details of a drawing can be extracted and can be freely combined with the content of other drawings or the above description unless the knowledge of a person skilled in the art stipulates otherwise and such a combination is explicitly prohibited here. In the schematic drawings:

[0034] FIG. 1a shows a side view of the adjustment device with an open valve and a tensioned pretensioning means;

[0035] FIG. 1b shows the adjustment device in FIG. 1a with a closed valve and a relaxed pretensioning means;

[0036] FIG. 2a shows the pretensioning means in a section II-II with a helical compression spring in the tensioned position in FIG. 1a;

[0037] FIG. 2b shows the pretensioning means in a section II-II with a helical compression spring in the relaxed position in FIG. 1b;

[0038] FIG. 3 shows in perspective an embodiment of the pretensioning means with a plurality of pretensioning springs,

[0039] FIG. 4 shows an embodiment of the adjustment device with an electromagnetic clutch, an electromagnetic tensioning means, and a mechanical resetting means,

[0040] FIG. 5 shows an embodiment of the adjustment device as in FIG. 4 but with a hydraulic resetting means,

[0041] FIG. 6 shows an embodiment of the adjustment device with an electromagnetic clutch, a hydraulic tensioning means, and a mechanical resetting means,

[0042] FIG. 7 shows an embodiment as in FIG. 6 but with a directional control valve between the hydraulic pump and the hydraulic cylinder, and

[0043] FIG. 8 shows an embodiment similar to FIG. 4 but with a module for the triggering means and the pretensioning means, and a module for the tensioning means, respectively.

[0044] FIGS. 1a and 1b show the adjustment device 1 with an open valve 2 and a tensioned pretensioning spring 16 (FIG. 1a) and with a closed valve 2 and a relaxed pretensioning spring 16 (FIG. 1b). The adjustment device 1 for a valve 2, with a drive means 3, with an actuating means 4, and with a pretensioning means 5 is shown.

[0045] The functional diagrams in FIGS. 1a and 1b show the actuating means 4 for operating the valve 2, for example a process valve, via which a volume flow 6 can be set. The actuating means 4 has a spindle drive with a drive means 3, for example an electric machine 7, which drives a spindle 8. A rotational movement of the spindle 8 is effected about the longitudinal axis 10 in the direction of the arrows A or B. In the example illustrated, the rotational movement of the spindle 8 is transmitted to a ball element 11 of the valve 2, with a through bore 12, which is mounted in sealing fashion in a valve housing 13. A valve duct 14 passes through the valve housing 13, is continued at its mouths by tubes 15, and a gaseous or liquid medium (volume flow 6) flows therein.

[0046] A cavity, in which the ball element 11 with the bore 12 (flow opening) is mounted rotatably, is formed in the valve housing 13. The ball element 11 is attached coaxially to the drive end 8.2 of the spindle 8. In the situation in FIG. 1a, the bore 12 and the valve duct are aligned with each other, the whole flow opening is unblocked, and the valve 2 is therefore open. When the ball element 11 rotates by 90° in the direction of the arrow C or D, the ball element 11 and the valve duct 14 cover each other, the flow opening is blocked, and the valve is closed (see FIG. 1b).

[0047] The electric machine 7 is arranged at the drive end 8.1 of the spindle 8. By activating the electric machine 7, it is possible in normal operation to adjust the ball element 11 of the valve 2 depending on the rotational movement of the threaded spindle 8 in the direction of the arrows C or D, via the rotational movement of the drive shaft 24 of the electric machine 7 in the direction of the arrows E and F, the rotational movement of the spindle 8 in the direction of the arrows A and B, and the rotational movement of the drive axis 25 of the valve 2 in the direction of the arrows C and D.

[0048] In the case where the valve 2 has been activated (opened) and hence a certain volume flow 6 has been set, in the event of a power failure or a system-side fault, the valve 2 would remain open such that the functioning of the process valve can no longer be controlled. For such a fault, an emergency operation means is provided by means of which the spindle can be reset to a default position in which the valve 2 is closed (FIG. 1b). In the solution shown in FIGS. 1a and 1b, this resetting is effected mechanically, there being no need for any structural elements to be operated electrically for the emergency function. The emergency operation device consists essentially of an energy storage system, in the present case consisting of the pretensioning means 5 with a pretensioning spring 16 (spring-activated mechanism).

[0049] As shown in FIGS. 2a and 2b, the pretensioning spring 16 is supported at one of its ends on a first support element 17 which is fastened such that it can rotate via a first pivot point 19 on a stationary pivot bearing 21. The pretensioning spring 17 is supported with its other end on a second support element 19 which engages with one end of a lever arm 9 via a second pivot point 20. The lever arm 9 or an equivalent element is fastened fixedly to the spindle, for example by adhesive bonding, welding, screws, or the like, and is consequently rigidly connected to the spindle 8.

[0050] FIGS. 1a and 2a show the pretensioning spring 16 in a tensioned position, whereas FIGS. 1b and 2b show the pretensioning spring 16 in a relaxed position. In the course of the relaxation of the pretensioning spring 16, for example a helical pressure spring, the second support element 18 moves in the direction of the arrow H from the first position 18′ (FIG. 2a) into a second position 18″ (FIG. 2b). The lever arm 9 is hereby pressed upward such that the spindle 8—viewed in cross-section—is rotated by an angle α=90° about its actuating shaft 10 (longitudinal axis). In this way, the ball element 11 of the valve 2 is likewise rotated by 90° into the closed position (FIG. 1b). The arrow d shows the direction in which the pretensioning spring 16 is tensioned.

[0051] FIG. 3 shows in perspective an embodiment of the pretensioning device 5 with a plurality of pretensioning springs 16.sub.1 to 16.sub.n (spring pack). The pretensioning springs 16.1 to 16n can be arranged connected in series or in parallel. A track guide is designated by 22 and a retaining element for the pretensioning means 5 is designated by 23.

[0052] FIGS. 4 to 8 show different embodiments of the adjustment device 1. For the sake of simplicity, the pretensioning means 5 is shown by way of example as a helical spring. It is intended that the spindle 8 which is shown as being bent illustrates purely schematically that the movable end of the pretension means 5 is configured to exert a torque on the spindle 8.

[0053] The different designs shown in FIGS. 4 to 8 each comprise a drive for a tensioning means 26 for tensioning the pretensioning means 5, the pretensioning means 5 (fail-safe system), a triggering means 27 for the pretensioning means 5, and a resetting means 28.

[0054] FIG. 4 shows an embodiment of the adjustment device 1 with the following elements: the drive for the tensioning means 26 is effected by a first electromotor 29 which interacts with the spindle 8 via a first transmission 32. The pretensioning means 5 comprises an elastic element, for example a spring element. The triggering means 27 has an electromagnetically operable clutch 35, which acts as a brake, and interacts with the spindle 8 via a second transmission 33. The resetting means 28 is substantiated in mechanical form, for example via the drive means 3 with the drive shaft 24. An interface between the drive means 3 and the spindle is designated by 35. A position detector is designated by 40.

[0055] According to FIG. 5, an adjustment device 1 is provided as in FIG. 4 but with a hydraulic resetting means 28. A hydraulic circuit is present for this purpose which comprises a first hydraulic pump 36 and a hydraulic motor 38 which are arranged as a rotary drive inside the spindle between the drive means 3 (see FIG. 4) and the pretensioning means 5. This design enables a lower speed and lower forces.

[0056] FIG. 6 illustrates an adjustment device 1, in which the tensioning means 26 comprises a second hydraulic pump 37, driven by a second electromotor 30, which acts on a linear hydraulic cylinder 39. The tensioning means 26 is substantiated in electrohydraulic form.

[0057] FIG. 7 illustrates an adjustment device 1, in which a directional control valve 42 with an electromagnet and spring return is interposed between the second hydraulic pump 37 and the hydraulic cylinder 39 in a hydraulic line 41.

[0058] FIG. 8 shows an adjustment device 1 with a first module 43 and a second module 44. The first module 43 comprises the triggering means 27 and the pretensioning means 5. The second module 44 contains the tensioning means 26. In a multi-valve system, a first module 43 can be associated with each of the valves 2. The second module 44 can be connected as required to one of the multiple first modules 43. A third transmission is designated by 34.

LIST OF REFERENCE SYMBOLS

[0059] 1 adjustment device

[0060] 2 valve

[0061] 3 drive means

[0062] 4 actuating means

[0063] 5 pretensioning means

[0064] 6 volume flow

[0065] 7 electric machine

[0066] 8 spindle

[0067] 8.1 drive end

[0068] 8.2 drive end

[0069] 9 lever arm

[0070] 10 actuating shaft

[0071] 11 ball element

[0072] 12 bore

[0073] 13 valve housing

[0074] 14 valve duct

[0075] 15 tube

[0076] 16 pretensioning spring

[0077] 16.sub.1 to 16.sub.n pretensioning springs

[0078] 17 first support element

[0079] 18 second support element

[0080] 18′ first position

[0081] 18″ second position

[0082] 19 first pivot point

[0083] 20 second pivot point

[0084] 21 pivot bearing

[0085] 22 track guide

[0086] 23 retaining element

[0087] 24 drive shaft

[0088] 25 drive axis

[0089] 26 tensioning means

[0090] 27 triggering means

[0091] 28 resetting means

[0092] 29 first electromotor

[0093] 30 second electromotor

[0094] 31 third electromotor

[0095] 32 first transmission

[0096] 33 second transmission

[0097] 34 third transmission

[0098] 35 interface

[0099] 36 first hydraulic pump

[0100] 37 second hydraulic pump

[0101] 38 hydraulic motor

[0102] 39 hydraulic cylinder

[0103] 40 position detector

[0104] 41 hydraulic line

[0105] 42 directional valve

[0106] 43 first module

[0107] 44 second module