EP2597209B1 - Electronic-hydraulic hoisting gear regulation system - Google Patents

Description

The invention relates to an electronic-hydraulic hoist control system according to the preamble of patent claim 1.

At the EP 2 031 256 A known Hubwerksregelsystem is a four-position four-way gate valve with two proportional solenoids and two Druckvorsteuerungen provided for the purpose of load pressure independence on the pump side a supply regulator pressure compensator and on the side of the hoist lifting cylinder associated with a lifting pressure compensator and a lowering pressure compensator. In the case of a single-acting lifting cylinder whose lifting side is assigned by a proportional solenoid controllable pressure relief valve to the return. In addition to multiple EHR functions, a float position function for the lift cylinder is adjustable in one of the four control positions of the 4/4 damper pressure control valve. For a single-acting lifting cylinder in this case the construction effort is enormous, especially with the leakage-laden four-position slide valve.

Further state of the art for electronic-hydraulic hoist control systems can be found in DE 10 2005 005 314 A and one already in the September 1999 published catalog with the registration number 1 987 760 507 / 09.99 "EHR" the company Rexroth, pages 2/55 to 8/55 , wherein therein the operable with two proportional solenoid pressure control valve for each single-acting lifting cylinder of a front and a Heckhubwerks each a structurally complex, leak-prone three-position three-way gate valve.

In the European patent application with the file number 10 195 693.6 with older seniority is proposed for an electronic-hydraulic Hubwerksregelsystem for a single-acting lifting cylinder, each operated by a proportional solenoid via a pressure feedforward, to use pressure-independent regulating 2/2-pressure control valves in poppet design for the EHR functions. A floating position function is not disclosed. A load pressure signal circuit section is directly connected to the supply control of the pump.

Further prior art can be found in: US 2009/050222 A1 . US Pat. No. 6,397,655 B1 . US 2004/188113 A1 and DE 203 17 749 U1 ,

The invention is based on the object, an electronic-hydraulic Hubwerksregelsystem of the type mentioned, i. with many different EHR functions, despite being a floating position function structurally simple and quickly appealing.

The stated object is achieved with the features of claim 1.

Since the two pressure control valves strictly regulate load pressure independent leak-free shut-off, all the usual EHR functions can be performed, the structural complexity is low and because of less restrictors and simple and direct flow paths in the system rapid response is ensured at least when initiated by the controller functional changes. The float position function is set via the control unit on the 2/2-way pressure control valve, at which time the 2/2-black / white solenoid valve shuts off the load pressure signal circuit section in order to prevent unwanted reactions of the hoist control system and / or the pump due to load pressure signal influences. excluded. The floating position function selectable in this way via the EHR control unit makes it possible, for example, to have an attachment on the hoist, such as a plow, snow plow or mower, follow ground unevenness in ground contact under all or part of its own weight, regardless of relative movements of the vehicle Vehicle body of the vehicle equipped with the hoist.

Suitably, the solenoid valve in the signal circuit section is designed as a seat valve and connected so that when energized black and white magnets, the passage position is adjusted and held by the closing spring. The shut-off position results in selected via the control unit floating position function with energized black and white magnet. In the shut-off position leakage is given in one or both flow directions. Alternatively, the solenoid valve could be reversed.

In an expedient embodiment, the 2/2-lift pressure control valve can be brought to an at least substantially unthrottled passage position at maximum current supply of the proportional magnet in order to have as little throttle loss as possible in the lifting control. By contrast, the 2/2-lowering pressure control valve can be brought into throttled passage positions with increasing energization of the proportional solenoid, for example, to produce a desirable hydraulic damping, or, preferably, in a regenerative operation from load movements fed back hydraulic pressure energy in a pressure accumulator or, preferably, one To achieve speed limit.

The pump in the pump / return arrangement may be a variable displacement pump or a fixed displacement pump. The variable displacement pump is controlled from the load pressure signal circuit or load pressure signal circuit section so that a higher flow rate is provided with increasing load pressure signal and is regulated down to a minimum flow rate when the load pressure signal is absent. The fixed displacement pump may contain a circulation circuit, optionally with a pressure compensator valve, as a supply control, which either directs the delivery rate to the return line can flow out or adapted to the needs of the flow or the pressure for the lifting cylinder provides.

In order to block the lifting cylinder hydraulically, for example when the pump is switched off, it is expedient if downstream of the 2/2-lifting pressure control valve in the direction of the pump blocking check valve is arranged.

In order to improve the energy balance of the system, it is also appropriate to a bypass of the 2/2-lifting pressure control valve between the pump and the node connected to a pressure accumulator, which is biased by a spring or by gas pressure, provides a certain pressurized removal volume and Recover energy when it is charged with the load pressure when the pump is shut down or regulated. Stored hydraulic pressure energy relieves the pump.

In the case of a pressure accumulator, upstream of the bypass line, a check valve blocking the direction of the pump is arranged to be able to charge the pressure accumulator not only by the pump but also by the load pressure, and is in the bypass line upstream of the node blocking towards the node Check valve arranged to prevent the automatic discharge of the pressure accumulator or adjusting the lifting cylinder without influencing the electronic-hydraulic Hubwerkregelsystems.

Since a load direction reversal on the hoist can not be excluded when the float position function is set, it is expedient if the 2/2-way pressure control valve acts as a suction check valve opening in the direction of the lifting side of the lifting cylinder. If there is a load reversal on the hoist, i. With a lift lifting the load acting on, then the lifting side of the lifting cylinder pressure medium from the return is sucked.

Since a largely ideal load pressure independence is important for a wide variety of EHR control functions and their perfect control, it is expedient if, in the respective pressure pilot control, the load pressure on the lifting side of the lifting cylinder is supplied with a proportional pressure acting against the load force of the proportional solenoid Adjusting force can be generated hydraulically, which gives the proportional solenoid feedback on the actual present load pressure situation, so that the pressure control valve in the interaction of the pressure precontrol and the actuating force acts load pressure independent. The actuating force can be generated in the pressure pilot control, for example, via an adjustable by the proportional variable throttle directly on the proportional solenoid, the variable throttle structurally incorporated easily into the pressure feedforward can be. Such load-independent working 2/2-pressure control valves in poppet design, for example, are known from EP 2 270 340 A whose overall disclosure is hereby incorporated by reference.

Fig. 1

eine Schemadarstellung eines Hubwerks, kombiniert mit einem Blockschaltbild eines Hauptteiles eines elektronisch-hydraulischen Hubwerksregelsystems EHR, in stromlosem Zustand, und

Fig. 2

eine durch einen integrierten Druckspeicher mit Energierückgewinnung betreibbare Ausführungsform.

Embodiments of the subject invention will be explained with reference to the drawings. Show it:

Fig. 1

a schematic representation of a hoist, combined with a block diagram of a main part of an electronic-hydraulic hoist control system EHR, in the de-energized state, and

Fig. 2

an embodiment operable by an integrated pressure accumulator with energy recovery.

Fig. 1 illustrates a block diagram of a main part of an electronic-hydraulic Hubwerksregelsystems E of a vehicle, not shown, which is equipped for example behind a rear axle or front of a front axle 2 with a hoist 1 (front or rear hitch). The hoist 1 has, for example in the manner of a three-point lifting device upper link 3, lower link 4 and intermediate link 6, wherein the lower link 4 an attachment point 5 for example, an attachment, such as a plow, a mower or the like., Is provided. The hoist 1 is operated with at least one single-acting hoist lifting cylinder Z, at the lifting side 8 a working line 7 is connected.

With the electronic-hydraulic hoist control system E u.a. perform multiple EHR control functions, which usually allow a position control, a draft control, a mixed control, a slip control, a pressure control, a force setting, a vibration damping, an external control, possibly a weighing function and the like in the vehicle, plus a floating position function, for example is needed so that an attachment on the hoist in ground contact uneven ground regardless of driving movements of the vehicle is able to follow, under the full dead weight or under an adjustable portion of its own weight.

The electronic-hydraulic Hubwerksregelsystem E is supplied from a pump / return assembly 9 with a pump 10, in the embodiment of a variable displacement, and a pressure medium vorhaltptenden return 13. The pump 10 is associated with a supply control 11, which may be incorporated into a load pressure signal circuit, not shown, and in the embodiment shown is connected to a load pressure signal circuit section 36 and, for example, the delivery rate or the pressure in a supply line 12 output of the pump 10 is adjusted depending on demand.

Alternatively, the pump 10 could be a constant-flow pump whose supply control 11 has, for example, a circulation control with a pressure compensator, which can either flow out into the return 13 depending on the load pressure signal or provide the delivery rate or the pressure as needed.

The electronic-hydraulic hoist control system E has at least one electronic control unit CU, which may have an input section 14, and is connected via lines 15 to various sensors (not shown) in the vehicle, hoist 1 or on the attachment. The sensors may be speed or velocity sensors, force sensors, position sensors and the like. Via lines 16, the control unit CU is further connected to electrical components of the hydraulic control between the pump 10 and the lifting cylinder Z.

The supply line 12 from the output of the pump 10 leads to a node 17 in the working line 7. Upstream of the node 17 and upstream of a branch 35, a 2/2-lifting pressure control valve 18 is arranged in a poppet-type, which is actuated by a proportional solenoid 20, a has load-independent pressure feedforward control 21, and is held by a spring 19 at de-energized proportional solenoid 20 in the shut-off position shown, in which the supply line 12 is shut off leak-free in the direction of the node 17. When current is supplied to the proportional magnet 20, corresponding pressure-regulating passage positions can be set for the energization, with an at least substantially unthrottled passage position 28 given at maximum current flow. From the branch 35, a pilot line 22 indicated by dashed lines can branch off to the pressure pilot 21 in order to report the load pressure acting on the lifting side 8 upstream in the passage positions of the 2/2-lift pressure regulating valve 18. The load pressure message can also be done without own pilot control line 22 in the interior of the 2/2-lift pressure control valve 18, and serves, for example, to generate a load force proportional to the load pressure via a variable from the proportional solenoid 20 variable throttle against the actuating force of the proportional solenoid, the proportional solenoid 20th processed as a controlled variable to be able to control load pressure independent. Furthermore, the load pressure signal circuit section 36 branches off from the branch 35 to the supply control 11. The section 36 may for example be incorporated via a not shown shuttle valve in the load pressure signal circuit, not shown, and performs a load pressure signal as soon as the proportional solenoid 20 of the 2/2-lift pressure control valve 18 is energized.

In a running from node 17 to the return line 13 a system pressure limiting valve 25 (secondary pressure limiting) is included, the response pressure is adjustable.

In a further, from the node 17 to the return line 13 extending line 26 is a 2/2-way pressure control valve 27 is included in the seat valve design, which has a proportional solenoid 30 for actuating a load pressure independent pressure pilot control 31. In the 2/2-way pressure control valve 27, although in the shut-off position set by a spring 29 when the proportional solenoid 30 is de-energized, leakage-free sealing at least in the direction of flow to the return 13 can prevail, but here e.g. paired with a Nachsaug-checkback function in the flow direction from the return line 13 to the node 17. Further, the 2/2-lowering pressure control valve 27, in contrast to the 2/2-lift pressure control valve 18 depending on the energization of the proportional solenoid 30 assume variable throttled passage positions 31. A dashed line indicated pilot line 32 may be provided to report the load pressure on the lifting side 8 to the pressure pilot 31, so that, as mentioned, here also with the proportional solenoid 30 is controlled by a load pressure-dependent force strictly independent of the load pressure. The load pressure can alternatively be tapped inside the valve 27 for generating the control force (elimination of pilot power 32).

Lastly, in the load pressure signal circuit section 36 is included a 2/2 black and white solenoid valve 37 having a black and white switching magnet 38 acting against a closing spring 39, e.g. is connected so that it holds when energized black / white magnet 38, the set by the closing spring 39 passage position, however, shuts off when energized the black / white switching magnet 38.

In the Fig. 2 shown embodiment of the electronic-hydraulic Hubwerksregelsystems E differs from that of Fig. 1 in that a regenerative operation with energy recovery is possible because a 2/2-lifting pressure control valve 18 bypassing line 40 leads from the supply line 12 to node 17, to which a pressure accumulator 41 (eg with gas pressure bias or spring preload) is connected. Furthermore, here is the output of the pump 10 a blocking to the pump check valve 42 is disposed, and upstream of the node 17 in the direction of node 17 blocking check valve 43. About the check valve 43, for example, when the pump 10 is switched off, the load pressure on the lifting side 8 of the lifting cylinder Z can be used to load the pressure accumulator 41, or can be used, for example, resulting from driving movements or when terminating a lowering movement of a load for this purpose load pressure increases. The recovered hydraulic pressure energy can be used to relieve the pressure of the pump 10 by first energizing the proportional solenoid 20 of the 2/2-lift pressure control valve 18, the stored energy the pressure accumulator 41 is used without the help of the pump 10. In addition, the pressure accumulator 41 to be charged also by the pump 10 allows a predetermined hydraulic damping effect.

In both embodiments, the proportional solenoid 20 is energized in a corresponding to the desired lifting speed corresponding extent to extend the lifting cylinder Z in de-energized proportional solenoid 30, the 2/2-black / white solenoid valve 37 is in the illustrated passage position and the load pressure at the junction 35 tapped and is transmitted to the supply control 11. The lifting movement of the lifting cylinder Z takes place at the selected speed load pressure independent. If the hoist 1 to block hydraulically or stop, both proportional solenoids 20, 30 are de-energized. In Fig. 2 For example, the load pressure on the lifting side 8 can load the pressure accumulator 41. If the hoist 1 lower, energized proportional solenoid 20 and de-energized black / white switching magnet 38, the proportional solenoid 30 is energized to control the lowering movement with a proportional to the current speed, for example, a certain damping or speed limit can be adjusted and initially, if necessary, the pressure accumulator 40 is loaded.

To set a floating position function for the hoist 1, the control unit CU switches the proportional solenoid 20 de-energized, the proportional solenoid 30 is optionally energized maximum, and at the same time the black / white switching magnet 38 is energized, so that in the shut-off position of the 2/2-lifting Pressure control valve 18, the 2/2-way pressure control valve 27 its throttling full passage position (or, if desired, a throttled intermediate-passage position) and at the same time the load pressure signal circuit section 36 is shut off, so that no load pressure signals to the supply control 11 arrive.

To both embodiments in Fig. 1 and 2 is indicated that the pressure control valves 18, 27 are ideal load pressure independent work, for example, accordingly EP 10 195 693.6 or maybe even EP 2 270 340 A , In an alternative, not shown, only the 2/2-lowering pressure control valve 27 could work independently of load pressure, because the 2/2-lift pressure control valve 18 is optionally supported by the supply control 11 via the load pressure signal so that in the combination load pressure independence is achieved.

Claims (9)

1. Electronic-hydraulic hoisting gear regulation system (E) for at least one single acting hoisting gear-lifting cylinder (z), comprising an EHR-control device (CU), a load pressure signal circuit, and at least one pressure regulating valve between a pump/return-assembly (9) and a lifting side (8) of the hoisting gear-lifting cylinder (z), the pressure regulating valve being actuatable by the control device (CU) via a proportional solenoid (20, 30), wherein the pump (10) is controlled by the load pressure signal circuit (4) for supplying a working line (7) extending to the lifting side (8), and wherein in addition to multiple EHR-regulating functions by the EHR-control device (CU) a floating position function of the lifting cylinder (z) can be adjusted, characterized in that a 2/2-lifting pressure regulating valve (18) designed as a seat valve and having proportional solenoids (20) and a load pressure independent pilot control (21) is arranged between the pump (10) and a knot (17) of the working line (7), that a 2/2-lowering-pressure regulating valve (27) designed as a seat valve and having proportional solenoids (30) and a load pressure independent pilot control (30) is arranged between the knot (7) and the return (13), and that in a section (36) of the load pressure signal circuit connected to a supplying regulating assembly (11) of the pump (10) and branching off between the 2/2-lifting pressure regulating valve (18) and the knot (17) a 2/2-black/white-solenoid valve (37) is provided, which is in a through-flow position when EHR-regulating functions are set and which is in a blocking position when the floating position function is adjusted and a proportional solenoid (30) of the 2/2-lowering-pressure regulating valve (27) is supplied with electric current.
2. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that the 2/2-black/white-solenoid valve (37) is a seat valve having a closing spring (39) for adjusting the through-flow position when the black/white-solenoid (38) is current-free, and that the seat valve can be switched into the blocking position with electric current supplied to the black/white-solenoid (38) and when the floating position function is selected by the control device (CU).
3. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that the 2/2-lifting-pressure regulating valve (18) can be switched to a through-flow position (28) substantially without then executing a throttling effect and with maximum electric current supplied to the proportional solenoid (20), and that the 2/2-lowering-pressure regulating valve (27) can be switched with increasing electric current supplied to the proportional solenoid (30) into through-flow position (34) only with a throttling effect, preferably, into proportionally variable throttling through-flow positions.
4. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that the pump (10) is either a variable capacity pump or a constant displacement pump, respectively having a supply regulation (11) for supplying the working line (7), the supply regulation (11) being connected at least with the load pressure signal circuit-section (36) containing the 2/2-black/white solenoid valve (37).
5. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that a check valve (23) is arranged between the branching-off (35) of the load pressure signal circuit-section (36) and the knot (17), the check valve (23) blocking in a direction toward the pump (10).
6. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that a pressure accumulator (41) having a spring pre-load or gas pressure pre-load connected with a deviating line (40) deviating from the 2/2-lifting-pressure regulating valve (18) between the pump (10) and the knot (17).
7. Electronic-hydraulic hoisting gear regulation system according to claim 6, characterized in that upstream of the deviating line (40), a check valve (42) blocking in a direction towards the pump (10) and in the deviating line (40) upstream of the knot (17), a check valve (43) blocking in a direction towards the knot (17) are provided.
8. Electronic-hydraulic hoisting gear regulation system according to claim 1, characterized in that the 2/2-lowering-pressure regulating valve (27), at least when the proportional solenoid (30) is current-free, functions as a suction-check valve (33) opening in a direction to the lifting side (8).
9. Electronic-hydraulic hoisting gear regulation system according to at least one of the preceding claims, characterized in that within or at the respective pilot control (21, 31) by the respective load pressure at the lifting side (8) and when the proportional solenoid (20, 30) is supplied with electric current, an actuating force can be generated hydraulically and counter to the actuating force of the proportional solenoid (20, 30), which actuating force is proportional to the load pressure, preferably by an adjustable aperture incorporated into the pressure pilot control (21, 31) and actuated by the proportional solenoid (20, 30).

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