The invention relates to a hydraulic valve device with a fluid connector arrangement containing at least the following:
DE 603 04 663 T2 discloses a hydraulic valve arrangement with a supply connector arrangement comprising a high pressure connector P and a low pressure connector T, a working connector arrangement comprising two working or utility connectors A, B that can be connected to a consumer, a directional valve, and a compensation valve located between the directional valve and the supply connector arrangement P, T, whose pressure output is connected to the pressure input of the directional valve, the compensation valve having a relief output which can be connected to the pressure output and a valve element in the form of a spool, which can be moved out of an initial position in opposite directions, and which can be exposed to pressure on one side in the load sensing line and to the force of a spring and, on the opposite side, can be exposed to the pressure at the pressure output, the valve element, when moved in one direction, performing a pressure control function, and, when moved in the opposite direction, performing a pressure relief function, the spool having a longitudinal channel which is connected via a transverse bore to the pressure output and ends in a first pressure chamber, and the longitudinal channel extending beyond the transverse bore and being connectable via a closable opening to a second pressure chamber in which a relief pressure prevails.
With this known solution, it is possible to counteract so-called parasitic pressure propagation, as can occur especially at higher pressures. When with the accompanying essentially inevitable leaks, the pressure propagates as far as an actuation motor which should not be actuated at all, but then sets it into motion, this can result in the unintended and hazardous raising of loads. In this connection, the safety valves which have been used in the past can, however, likewise be subject to leaks and can even contribute to the formation of the parasitic pressure propagation.
EP 1 370 773 B1 discloses a comparable directional control valve as a hydraulic valve device which is used for controlling the pressure and the flow of hydraulic oil from and to working connectors A, B of at least one fluid consumer, in which the pressure and flow rate can be controlled by means of a valve spool which can be moved in the spool bore and which can be actuated by at least one drive, and by means of annular channels dynamically connected thereto, at a so-called symmetry center point, on the axis of symmetry of the valve device there being a tank connector annular channel as a so-called return flow connector and on both sides other annular channels being arranged likewise symmetrically to the axis of symmetry. Due to the indicated symmetrical structure, in the known solution it has a simple solution from a mechanical viewpoint and thus allows economical fabrication. The known valve device intended to also have improved dynamic switching behavior and a wide scope of operation.
The known solutions, however, overall are still complex in production and for any fluidic application generally must be matched and designed accordingly. The known solutions in the prior art with respect to operating reliability still leave much to be desired.
Proceeding from this prior art, the object of the invention is therefore to further improve them while maintaining their advantages such that operating reliability is still further improved and that the solution according to the invention can be well executed relative to changing applications in terms of a modular system. This object is achieved by a hydraulic valve device with the features of claim 1 in its entirety.
In that, as specified in the characterizing part of claim 1, the control means is provided with load reporting and load sensing connectors which, interconnected in pairs, assign one load reporting connector to one load sensing connector and which, depending on the position of movement of the control means, interconnect at least some of the connectors of the fluid connector arrangement to carry fluid, the control means as a modular block concept can be easily adapted to different fluidic applications without greater modification or adaptation efforts to the hydraulic valve device thus becoming necessary. Due to the asymmetrical structure of the control means, which acts in this respect on the fluid connector arrangement, reliable triggering behavior is achieved and the control means thus can be moved with an extremely favorable dynamic displacement behavior exactly into operating positions. The solution according to the invention, viewed mechanically, is short, so that all relevant switching and control positions for the hydraulic valve devices can be implemented in a small installation space. In one especially preferred embodiment of the hydraulic valve device, according to the invention, it is provided that the control means can also assume a so-called floating position without loss of resolution in the lowering and lifting region relative to the working or utility connectors A, B. Although, as shown, the proportional region is fully preserved in lifting and lowering, due to the special concept of the control means, the length of the housing still is kept short overall, to which the asymmetrical structural concept of the hydraulic valve device also contributes.
In another especially preferred embodiment of the solution according to the invention, upstream from the control means a pressure compensator is connected, with which so-called quantitative cutoff by load sensing pressure limitation in the spring chamber of the pressure compensator is possible. In the solutions known in the prior art with a downstream pressure compensator, this function of quantitative cutoff is not possible or can be obtained in a complex manner only by way of corresponding additional valve structures. In particular, the control function of the pressure compensator is improved by a relatively large drainage cross section discharging into the return flow connector. The so-called floating position is also improved.
The hydraulic valve device according to the invention is detailed below using different exemplary embodiments. The FIGS. are schematic and not to scale.
The control means 18 as such is triggered conventionally and therefore is no longer detailed as conventional pilot valves 20, 22 which are reproduced in
The indicated control means 18 has a valve spool 28 which can be moved horizontally, when viewed in the direction of looking at
The type of possible switching positions follows from the conventional switching representation as shown in
For producing the channel routing, the middle channel 40 is bordered by an insertion sleeve 44, which at least partially along its outside periphery, located in a definable middle region, with the inside wall of the valve spool 28 in this region borders the annular longitudinal channel 42 which can also be formed here from a plurality of individual channels (not shown) which are located concentrically to the middle channel 40. The axial length of the insert sleeve 44 extends, as shown in
As
Overall, the hydraulic valve device forms a so-called LS directional control valve with an upstream pressure compensator 14. As the switching position as illustrated in
The hydraulic valve device according to the invention is made as a LS directional control valve with upstream pressure compensator 14 and has a valve axis configuration which is short in terms of overall length with few annular channels compared to known solutions. With the upstream pressure compensator 14 the already described function of quantitative cutoff by LS pressure limitation in the spring chamber of the pressure compensator 14 is possible.
The embodiment as shown in
In the embodiment as shown in
With the illustrated valve arrangement as shown in
With the valve device solution according to the invention, it is possible to achieve the combination of a floating position and a quick traverse in a mobile valve in a spool construction; this is especially efficient for use in conventional machinery (not shown) in which machines must be quickly moved and/or when they must be picked up and put down in the manner of a pivoting position; this is for example the case for a reciprocating finger bar mover of a slope mower or the like.
Since the reporting channel of the load sensing pressure must be opened into the spring chamber of the section pressure compensator over the entire stroke of the valve spool 28, the valve axis cannot be shortened relative to this function; this would benefit the overall size of the valve device. Conversely, an improvement can be achieved in the covering of the reporting bore on the valve spool 28. For the proposal according to the invention as shown in
In the neutral position of the valve spool 28 (shown in the upper half of the figure), the radial load sensing bore and the radial load reporting bore are each covered by the housing wall. The concept of a short construction dictates that in the “lifting” position (working position of the machinery) the load reporting bore of the connector A runs into the P connector and the load sensing bore into the R connector. To prevent short-circuiting from P to R a check valve 60 is installed in the corresponding connecting line 62. In the so-called lowering position and in the neutral position, a spring then holds the check valve 60 open so that here both pressure reporting, as well as dynamic flow which is dictated by the control movements of the connected pressure compensator 14, are ensured.
The pressure drop on the check valve for rapid control movements of the pressure compensator 14 and the spring force are matched to one another such that for rapid control movements as correspond to a high flow rate, the check valve 60 cannot close. In the lifting position, however, the leakage flow rate from P to R immediately becomes high enough for the pressure drop over the open check valve 60 to overcome the spring force and the check valve reliably closes. In this respect, therefore, the floating position is also reached by overtravel via the lowering position and the lifting position of the respectively connected machine. Here, it is possible that only when the machine has been placed, for example, on the ground in the lowered position is the floating position then engaged.
In the embodiment as shown in
With the valve device according to the invention, standard directional control valves with the three basic positions for neutral, lifting, and lowering can be expanded within the scope of operation to a floating position and/or a quick traverse position without the spool stroke being lengthened in doing so, as in the known spool valve solutions, in order to travel into the additional position with the desired logic operations; rather, with the solution according to the invention, this spool lengthening can be entirely avoided or the spool valve axis can be shortened.
Number | Date | Country | Kind |
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10 2007 054 137.8 | Nov 2007 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2008/008519 | 10/9/2008 | WO | 00 | 4/22/2010 |