EP2333351B1 - Electro-hydraulic lifting module - Google Patents

Description

The invention relates to an electrohydraulic lifting module according to the preamble of patent claim 1.

In such known from practice electro-hydraulic lifting modules can be despite a high control effort, the control characteristics to be desired, since starting phases when lifting or lowering and the stopping of a load are not sensitive to control. Furthermore, at the beginning of the energy recirculation mode of the pump, a surge occurs, which affects the Nebenverbrauchem. Since auxiliary consumers are usually connected via long hydraulic hoses, there is a striking movement and a disturbing noise due to such pressure surges. Although it is also known from practice to isolate the auxiliary consumers in this phase of operation by means of a solenoid valve, however, the precise control of this solenoid valve further increases the control engineering effort. The more solenoid valves are used in the lifting module, the higher the cost price.

At one off EP 2 058 270 Known lifting module are a lifting and a separate Senkstrang provided with appropriate solenoid valve fittings.

Out WO 97/28373 A is a lifting module, but known without energy return, in which three solenoid valves are connected in series in the main, one of which is formed with leak-tight dense shut-off.

Further prior art is contained in DE 10 2006 060 351 B3 and EP 1 898 104 A1 ,

The invention has for its object to provide an electro-hydraulic lifting module of the type mentioned above, the control technology is easy to operate, manages with a minimum number of solenoid valves, and is inexpensive to build.

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

By means of two 2/2-way solenoid seat valves arranged in series in the main line, which have the only electromagnets to be electrically controlled in the electrohydraulic lifting module, All functions can be controlled in a simple and simple way. The tapped via the branch line from the main line pressure or a corresponding pressure medium flow is to supplement the control of the various functions only on used hydraulic way. The further valve assembly of the electrohydraulic lifting module can only pressure-responsive automatically responsive valves or at least include a pressure compensator, which saves costs and allows a significantly improved control characteristics, especially because the start when lifting or lowering or energy return is controlled precisely and smoothly, as well Stopping the load. The valve, which can be actuated with a proportional solenoid, enables sensitive current and thus speed control during lowering. The other, operated by a black / white magnet valve is used for lifting control and, where appropriate, in the energy return. The at least one pressure balance, which is actuated at least from the branch line, is a structurally simple and functionally reliable valve and can be profitably used for a wide variety of control functions in the electrohydraulic lifting module. For example, this pressure compensator can also help to isolate secondary consumers from the main line at the beginning of an energy return mode of the pump so that pressure surges do not affect the secondary consumers or their connection hoses. The basic concept with the two 2/2-way magnetic seat valves connected in series in the main line and the branch line branching off to at least one pressure balance makes it possible to adapt the electrohydraulic lifting module to a wide variety of user-specific requirements in a universal manner, while always achieving a perfect control characteristic with a cost-effective design To achieve assembly costs.

Suitably, the 2/2-way solenoid seat valve is arranged with the black / white switching magnet in the flow direction to the hydraulic motor upstream of a 2/2-way magnetic seat valve with the proportional solenoid. The 2/2-way magnetic seat valve with the black / white solenoid and the leakage-tight in both directions sealable shut-off can then be used for redundancy protection, for example, if a 2/2-way solenoid seat valve with the proportional solenoid should have leakage or hang , Alternatively, these two valves may be provided in mutually reversed positions.

Further, it is expedient to form each of the 2/2-way magnetic seat valves with an actuatable by the respective magnet pressure precontrol to get along with a small and inexpensive magnet, even if high pressures or large amounts are to be mastered.

Depending on the desired design of the electrohydraulic lifting module, the branch line can either be only a pilot line, flow in the small pilot quantities, or a working pressure medium line, which is able to control the entire working pressure and additionally fulfills a pilot function.

The electro-hydraulic lifting module is particularly useful for industrial trucks, cranes, lifting platforms, concrete pumps or the like., Without being limited in use to these examples.

Depending on user-specific or application-specific requirements, the electrohydraulic lifting module may have either a two-quadrant pump as the sole pressure source, or a single-quadrant pump, both of which are operable in the energy return mode, and then recover electrical energy, for example, from the amount of pressure fluid displaced by the load, in which normally the pump driving electric motor is driven by the pump and works as a generator. In the case of a two-quadrant pump, it is fed either directly from the main line in the energy return mode, or from an extension line of the branch line fed back into the main line. In the case of a quadrant pump, it is fed in the energy return mode in the same flow direction as when lifting from an extension line of the branch line, wherein the suction side of the pump is isolated from the tank by a check valve closing to the tank. The respective pump can be operated at variable speed, wherein the two-quadrant pump may be, for example, a gear pump or an axial pump, while the single-quadrant pump may be of any type.

In an expedient embodiment and when using a two-quadrant pump, the branch line designed as a pilot control line is connected to the closing pilot port of the pressure compensator arranged in the supply line, whose pilot opening control port can be supplied with control pressure from the main line. The pressure compensator is placed in the shut-off position by the pressure signal in the branch line, in which the supply line to the secondary consumer is interrupted, so that in the energy return mode (and when lifting) from the main line no pressure surges to secondary consumers. At least when lifting the auxiliary consumer can not be controlled. If, on the other hand, the secondary consumer is to be controlled, then the pressure compensator optionally acts as a feed regulator to the secondary consumer. Optionally, the secondary consumer is associated with a circulation valve, which then the pressure medium in Let the tank flow essentially unthrottled if the pump should be switched on when the hydraulic motor and any auxiliary consumers are not operated. In this simple embodiment of the electro-hydraulic lifting module is very inexpensive and reliable.

If user-specific load-independent operation of the electro-hydraulic lifting module is required, in the electro-hydraulic lifting module, a load pressure signal circuit can be incorporated, which is fed from the branch line and possibly by auxiliary consumers. The arranged in a connecting line from the supply line to the tank pressure compensator is applied from the load pressure signal circuit also from the branch line forth at the closing pilot port, at the opening pilot port, however, from the supply line. The arranged in the supply line pressure compensator isolated at the beginning of an energy return mode, the auxiliary consumers from the main, so that no pressure surges for the auxiliary consumers to effect when the pump is fed directly from the main line in the energy return mode. Advantageously, the second pressure compensator acts in the connecting line between the supply line and the tank as required as a circulation valve, the pressure medium can flow with little loss to the tank while the pump is running and without actuation of consumers. The two pressure compensators regulate only pressure-dependent without any magnetic actuation and use the pressure signal in the branch line, also to control load-independent. This embodiment of the electrohydraulic lifting module can also be operated independently of the load without the pressure compensator in the supply line in order to be able to use only the desirable circulation valve function.

In a further expedient embodiment, in addition to the pressure balance between the branch line and the extension line, via which the working pressure medium is returned to the main line for the energy return mode, the supply line is connected to the main line via a pressure-controlled 3/2-way priority valve in the main line, to feed the secondary consumer, for example, when lifting a load with excess pressure medium, which does not need the hydraulic motor in this phase, or to feed only the one or more auxiliary consumers while the hydraulic motor is stopped and holds the load.

In a further embodiment with a two-quadrant pump, the pressure compensator is arranged between the branch line and the extension line. Its port pilot port is pressurized from the branch line with pilot pressure while the closing pilot port of this pressure compensator from the main line can be acted upon with control pressure. In a connecting line from the main line to the tank, a further pressure compensator is arranged, whose opening pilot port from the branch line and its closing pilot port from the main line are each acted upon with pilot pressure. In this embodiment, the further pressure compensator acts as a circulation valve to return the pressure medium to the tank with little loss while the pump is running and no decrease from a hydraulic load, and also to drain the pressure medium after passage through the pump with low loss to the tank in the energy return mode, if no secondary load power decreases. This embodiment may also be equipped with the priority valve in the main line, for example, to give priority to the hydraulic motor over secondary consumers, and to provide auxiliary consumers with excess pressure medium, if the hydraulic motor less decreases than the pump promotes.

In a further embodiment with a single quadrant pump, the pressure balance is arranged between the branch line and the extension line, which returns the working pressure medium to the main line during lowering and in the energy return mode of the pump, controlled by the pressure compensator arranged between the branch line and the extension line. In this case, it may be appropriate to associate the secondary consumers with a pressure-responsive recirculation valve that conducts excess pressure fluid into the tank with little loss when the pump is running or in its energy recirculation mode, if no secondary load decreases power. Preferably, the supply line is even connected via a pressure-controlled, arranged in the main line 3/2-way priority valve to the main line. The priority valve gives priority to the hydraulic motor. The one or more auxiliary consumers are thus further isolated against pressure surges in the energy return mode of the pump, since at most first flows through the pump pressure medium flows into the supply line. The priority valve is a preferred option in this embodiment and may be omitted in a more cost effective and structurally simple variant.

In a further expedient embodiment, in addition to the pressure balance between the branch line and the extension line in a connecting line from the main line to the tank, a further pressure compensator is arranged. Their port pilot port is pressurized with pilot pressure from the branch line while whose closing pilot port with pilot pressure from the main line can be acted upon, so that this additional pressure compensator, if necessary, acts as a circulation valve to the tank.

If in a further advantageous embodiment, the priority valve is provided in the main line, then this should be acted upon at a closing pilot port for isolating the supply line from the main line via a diaphragm with control pressure from the branch line, however, at an opening pilot port for on-demand connection Supply line to the main line with control pressure from the main line are acted upon.

In a further embodiment, the opening pilot ports of the arranged between the branch line and the extension line pressure compensator and arranged in the connecting line between the main line and the tank further pressure compensator are each directly connected via a control line to the branch line, while the closing pilot ports of the pressure compensator and the priority valve are each connected via a diaphragm containing a pilot control line to the branch line. The diaphragms have the task of ensuring the correct response of the respective pressure compensator depending on the pressure signal in the branch line (sequential control), that the passage from the branch line to the extension line is opened especially in the energy recirculation mode of the single-quadrant pump, and also the passage from the main line to the tank. if no secondary consumer performance decreases. It may be expedient if the set pressure of the further pressure compensator is higher than that of the pressure compensator between the branch line and the extension line.

All embodiments are characterized in particular by the fact that the two 2/2-way magnetic seat valves are connected in series in the main line between them via the branch line, a pressure signal is derived, either as a pilot pressure or as a load pressure with pilot function, and that on the Branch line at least one pressure compensator, optionally combined with at least one further pressure compensator and / or a priority valve is purely hydraulically controlled in order to achieve overall cost-effective without further Magnetbestückung an improved control characteristics of the Hubmoduls.

Fig. 1

ein Blockschaltbild einer ersten Ausführungsform eines elektrohydraulischen Hubmoduls, in drucklosem, nicht bestromten Zustand,

Fig. 2

eine gegenüber Fig. 1 um eine weitere Druckwaage erweiterte Ausführungs- form,

Fig. 3

eine weitere Ausführungsform mit einem Lastdrucksignalkreis,

Fig. 4

eine weitere Ausführungsform mit einer anders verschalteten Druckwaage und ergänzt durch ein Prioritätsventil,

Fig. 5

eine weitere Ausführungsform,

Fig. 6

eine weitere Ausführungsform mit einer Einquadrantenpumpe,

Fig. 7

eine weitere Ausführungsform, ähnlich der von Fig. 6, jedoch ergänzt mit ei- nem Prioritätsventil,

Fig. 8

eine weitere Ausführungsform, ähnlich der von Fig. 6, ergänzt mit einer weite- ren Druckwaage, und

Fig. 9

eine weitere Ausführungsform, ähnlich der von Fig. 8, ergänzt mit einem Prio- ritätsventil.

With reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

1 is a block diagram of a first embodiment of an electrohydraulic lifting module, in a pressureless, non-energized state,

Fig. 2

one opposite Fig. 1 extended by another pressure compensator,

Fig. 3

another embodiment with a load pressure signal circuit,

Fig. 4

a further embodiment with a differently connected pressure compensator and supplemented by a priority valve,

Fig. 5

another embodiment,

Fig. 6

a further embodiment with a single-quadrant pump,

Fig. 7

another embodiment, similar to that of Fig. 6 , but with a priority valve,

Fig. 8

another embodiment, similar to that of Fig. 6 , supplemented with another pressure compensator, and

Fig. 9

another embodiment, similar to that of Fig. 8 , supplemented with a priority valve.

In the Fig. 1 to 9 Electro-hydraulic lifting modules M, each shown as a block diagram, which are intended for example for use in industrial trucks, cranes, lifting platforms, concrete pumps, or similar hydraulically controlled systems.

All in the Fig. 1 to 9 shown embodiments are used for direction and speed control of a hydraulic motor H, which is acted upon by a load L, preferably a single-acting lifting cylinder, which is connected via a lowering brake 2 to a main line 1, which is connected to a pump 3. The pump 3 is also operable in an energy recirculation mode to drive the electric motor 5 driving the pump 3 as a generator when lowering the load, and to generate electric power. The pump 3 is connected via a filter and damping device 6 with a check valve grouping to the main line 1 and assigned to a tank R. The main line 1 is secured by a pressure relief valve 7 and a tank line 8. In the main line 1, two 2/2-way magnetic seat valves V1, V2 are connected in series, between which branches off at a node 17, a branch line Z. Furthermore, branches off between the pump 3 and the 2/2-way solenoid seat valves V1, V2 at a node 9 from a supply line 10 to which at least one auxiliary load N is connected, preferably via valve components, not shown.

The one 2/2-way magnetic seat valve V1 is actuated by a proportional solenoid 12 against a spring 11, preferably via a pressure pilot 13, and is designed so that it can assume a passage position and a leak-free in the direction of flow to the pump closed shut-off position 14. Das Another 2/2-way magnetic seat valve V2 is actuated by a black / white switching magnet 15 against the spring 11, preferably via the pressure pilot control 13, and has a free passage position in both flow directions and a leak-tight in both directions of flow shut-off position 16. In all the embodiments shown, the other 2/2-way magnetic seat valve V2 upstream of the one 2/2-way magnetic seat valve V1 is arranged in the flow direction to the hydraulic motor H. This has the advantage that the other 2/2-way magnetic seat valve V2 in the event of a malfunction of a 2/2-way magnetic seat valve V1 (in case of leakage and / or snagging) can be actuated as redundancy protection to ensure that the load L is held. However, the arrangement of the two 2/2-way magnetic seat valves V1, V2 can also be reversed. In all embodiments, the branch line Z leads to at least one pressure compensator D and / or D1 and / or D2 and / or D3.

In the embodiments in FIGS Fig. 1 to 5 it is in the pump 3 to a two-quadrant pump 4, the electric motor 5 is reversible to work as a generator, while in the Fig. 6 to 9 the pump 3 is a single-quadrant pump 38 whose electric motor 5 has the same direction of rotation in normal operation and in the energy return mode of the single-quadrant pump 38. For example, the two-quadrant pump 4 is a gear pump or a piston pump, possibly even a regulating or variable displacement pump, while the single-quadrant pump 38 may be a piston pump, optionally a regulating or variable displacement pump, of any design.

The structurally simple and inexpensive embodiment in Fig. 1 is characterized in that the pressure compensator D is arranged in the at least one auxiliary consumer N branching supply line 10 and at a closing pilot port 21 parallel to a control spring 19 with control pressure from the control line 18 formed as branch line Z can be acted upon with pilot pressure, the the node 17 of the main line 1 when lifting and in the energy return mode of the pump 3 is tapped. For lifting control, the black / white switching magnet 15 of the other 2/2-way magnetic seat valve is energized. The speed of movement when lifting the load L can be generated by a speed control of the electric motor 5 (or a control of the two-quadrant pump 4). To lower the load L of the proportional solenoid 12 of a 2/2-way magnetic seat valve V1 is energized, the current setting the lowering speed (pressure or volume control), at the same time the black / white switching magnet 15 is energized, so that the two-quadrant pump 4 is fed in the energy return mode from the main line 1, wherein the pressure compensator D shuts off the supply line 10. In the energy return mode, the two-quadrant pump 4 delivers into the tank R, driving the generator / electric motor 5. The pressure compensator D is acted upon at an opening pilot port 22 via a control line 20 from the supply line 10 with control pressure which is lower in the energy return mode than the control pressure from the branch line Z acting parallel to the control spring 19 closing pilot port 21st

At least when lifting a load L by means of the hydraulic motor H, no auxiliary load N can be fed. When not energized black / white solenoid 15, however, controls the control pressure in the control line 20, the pressure compensator D against the control spring 19, so that at least one auxiliary load N is fed with pressure medium. In the embodiment in Fig. 1 It may be appropriate to the secondary consumer a circulation valve (not shown) assigned, which then dissipates the funded by the pump 3 pressure loss to the tank R, if neither the hydraulic motor H nor a secondary consumer performance decreases.

The embodiment of the electro-hydraulic lifting module M in Fig. 2 is different from that of Fig. 1 in that, in addition to the pressure compensator D in the supply line 10, a further pressure compensator D1 is arranged in a connecting line 36 'from the supply line 10 to the tank R or the tank line 8, which acts as a low-loss circulation valve, for example, if the hydromotor is running when the two-quadrant pump 4 is running H and / or secondary consumer N take no or less power than provided by the pump. The set pressure of this further pressure compensator D1 should be set differently than the set pressure of the pressure compensator D. The further pressure compensator D1 is connected to an opening pilot port via a control line 24 from the connecting line 36 '(or the supply line 10 or the main line 1) with control pressure acted upon, however, at a closing pilot port 25 from an incorporated into the electrohydraulic lifting module M load pressure signal circuit LS, to ensure that the electro-hydraulic lifting module M operates independently of the load. The load pressure signal circuit LS is fed via a further control line 18 'from the here designed as a control line 18 branch line Z, and also from the respective auxiliary consumer forth via a load pressure control line 18 ", wherein a shuttle valve 23 in the load pressure signal circuit LS each higher control pressure to the closing pilot port 25 of the further pressure balance D1 passes.

The embodiment of the electro-hydraulic lifting module M in Fig. 3 is similar to the Fig. 2 because in the connecting line 36 'between the supply line 10 and the tank R, the further pressure compensator D1 arranged and also the load pressure signal circuit LS are provided. However, that is in the Fig. 1 and 2 shown pressure balance D omitted here, so that in the energy return mode of the two-quadrant pump 4, a secondary load N from the supply line 10 is fed, or instead of energy recovery mode only the auxiliary consumers is fed, possibly even supplemented by a then lower pump delivery. The branch line Z is in Fig. 3 Also formed as a control line 18, and connected to the control line 18 'to the shuttle valve 23 and the closing pilot port 25 of the further pressure balance D1. In this structurally simple and inexpensive embodiment in Fig. 3 For example, the further pressure compensator D1 is particularly useful when the Zwequadrantenpumpe 4 is a gear pump, for example, when starting up to a speed of about 300 U / min has an extremely poor efficiency and therefore loss in the start-up on the further pressure scale D1 loss in the Tank should promote to exceed this speed limit as quickly as possible.

The embodiment of the electro-hydraulic lifting module M in Fig. 4 is different from those of Fig. 1 to 3 Mainly in that in the energy return mode of the two-quadrant pump 4, this is not fed directly from the main line 1, but via the branch line Z, which is designed here as Arbeitsdruckmittelleitung 26, and via a connecting line 27 to a arranged between the two-quadrant pump 4 and the node 9 node 28th is connected in the main line 1. In the energy return mode or for sink control, the black / white switching magnet 15 need not necessarily be energized here. Between the branch line Z and the extension line 27, a further pressure compensator D2 is arranged, the opening pilot port 30th via a control line 29 from the branch line Z can be acted upon with control pressure, while the closing pilot port 31 is acted upon parallel to the control spring via a control line 32 from the main line 1 with control pressure, so that the further pressure compensator D2 the flow in the energy return mode (possibly also when lowering ) controls.

In addition, the supply line 10 is connected to at least one auxiliary consumer via a arranged in the main line 1 3/2-way priority valve P to the main line 1. The priority valve P is acted on at a closing pilot port for isolating the supply line 10 from the main line 1 via a diaphragm 34 and a control spring 33 from the control line 29 with a derived from the branch line control pressure, while at the other pilot port via a priority valve between the P and the other 2/2-way magnetic seat valve V2 connected control line 35 from the main line. 1

At least in the energy return mode, the further pressure compensator D2 is opened, so that the two-quadrant pump 4 runs in the opposite direction of rotation and drives the electric motor / generator 5. If, for example, to lower the load L and the black / white solenoid 15 is energized, then the priority valve P can also feed the supply line 10 when the control pressure in the control line 35 is correspondingly high. On the other hand, during normal operation of the two-quadrant pump 4, the supply line 10 can feed the supply line 10 accordingly both when lifting a load and when the load is stopped. In this embodiment, it may be appropriate to the auxiliary load N assigned to a circulation valve, not shown, so that when powered Zwequadrantenpumpe 4 and without loss of power from the hydraulic motor H or a secondary consumer N the funded pressure medium is returned to the tank with little loss, outside of the electro-hydraulic lifting module M of Fig. 4 ,

In the embodiment of the electrohydraulic lifting module M in Fig. 5 will be similar to in Fig. 4 the working pressure medium in the energy recirculation mode of the two-quadrant pump 4 via the branch line Z and the extension line 27 at node 28 returned to the main line 1, bypassing the other 2/2-way magnetic seat valve V2, the further pressure compensator D2 between the branch line Z and the Extension line 27 arranged and as in Fig. 4 is pressure controlled. In a connecting line 36 between the main line 1 and the tank R and the tank line 8 is another pressure compensator D3 arranged, for example, acts as a circulation valve to relieve the two-quadrant pump 4. This additional pressure compensator D3 is acted on by an opening pilot port from the control line 29 from the branch line Z forth, however, at a closing pilot port via a control line 37 from the main line. 1

In the embodiments of the electro-hydraulic lifting modules in the Fig. 6 to 9 the pump 3 is a Einquadrantenpumpe 38 which is flowed through in the energy return mode in the same direction as in the working mode, wherein in the energy return mode, the working pressure medium via the branch line Z (working pressure medium line 26), the further pressure compensator D2 between the branch line Z and the extension line 27 at a Node 40 is fed to the suction side of the Einquadrantenpumpe 38 in the main line 1. The suction side of the single-quadrant pump 38 is protected from the tank R by a non-return valve 39 which blocks the tank. The additional pressure balance D2 will be as in Fig. 5 controlled on the one hand via the control line 29 and on the other hand via the control line 32. The supply line 10 branches off at the node 9 from the main line 1. In this case, it may be appropriate to associate a secondary valve with a circulation valve, which then returns the pressure medium loss in the tank when there is no power decrease with driven Einquadrantenpumpe 38. To lower the load L, either only the proportional magnet 12 or the switching magnet 15 is energized.

The further embodiment of the electrohydraulic lifting module M in Fig. 7 is the of Fig. 6 similar to that between the branch line Z (working pressure medium line 26) and the extension line 27, the further pressure compensator D2 is provided, which is at least turned on during the energy recirculation mode of the single-quadrant pump 38. In addition, here is a pressure-controlled 3/2-way priority valve P (similar to in Fig. 4 ) in the main line 1, which gives the hydromotor H priority over to the supply line 10 connected auxiliary consumers N, but a supply of secondary consumers N allows, if excess energy compared to the needs of the hydraulic motor H is present. The priority valve 8 is acted upon at the provided for isolating the supply line 10 closing pilot port from the control line 29 and the diaphragm 34 with control pressure, however, at the other pilot port via the control line 35 from the main line 1. Also in this embodiment, it may be appropriate to associate a circulation valve with at least one secondary consumer, which relieves the single-quadrant pump 38 when it is driven and no power reduction occurs.

In the embodiment of the electrohydraulic lifting module M in Fig. 8 the supply line 10 branches off the main line 1 directly at the node 9. In a connecting line 36 from the main line 1 to the tank R and the tank line 8, a further pressure compensator D3 is arranged (similar to in Fig. 5 for the two-quadrant pump 4), for the one-quadrant pump 38 in Fig. 8 a pressure relief takes place, if no performance decrease takes place. This further pressure compensator D3 is acted upon at the opening pilot side of the control line 29 from the branch line Z ago with control pressure, at the closing pilot side, however, from a control line 37 from the main line 1. At the beginning of an energy return mode, the supply line 10 through the then Power taken through Einquadrantenpumpe 38 isolated against harmful pressure shocks.

The embodiment of the electro-hydraulic lifting module M in Fig. 9 is that the Fig. 8 Similarly, because the further pressure compensators D2 and D3 are provided between the branch line Z and the extension line 27 or in the connecting line 36. In addition, however, the supply line 10 for auxiliary consumers N is as in Fig. 7 connected to the main line 1 via the 3/2-way priority valve P, which is controlled from the control lines 29 and 35. It is selected here a special interconnection of both pilot ports of the other pressure balance D2, which are applied equally from the branch line Z with control pressure, but the shutter pilot port 31, a diaphragm 41 is assigned, which ensures that at a pressure signal in the branch line Z the further pressure compensator D2 reliably aufsteuert to allow a power return mode of the single-quadrant pump 38 or to control the lowering of the load L. The priority valve P also makes it possible to supply secondary consumers N in the lifting control of the hydraulic motor H, if more power is provided than the hydraulic motor H consumes. Furthermore, the additional pressure compensator D3 fulfills the function of a circulation valve, if no power decrease takes place.

In all embodiments, the pressure compensators D, D1, D2, D3 structurally simple, cost-effective and reliable, purely hydraulically responsive valves that can take at least largely dense blocking positions with low production costs, optionally blocking positions, which are to be regarded as stacker-tight. If at least two pressure compensators are interconnected with equal priority on the pilot control side, it is expedient to design their control springs or set pressures differently or provide appropriate diaphragm combinations to achieve the required sequential control.

Claims (14)

1. Electro-hydraulic lifting module (M) for actuating at least one hydromotor (H) counter to a load (L), comprising a pump (3) connected by a main line (1) with the hydromotor (H), which pump is operable during lowering the load in an energy recovery mode, a solenoid valve assembly in the main line (1) for controlling lifting and lowering the load, and a supply line (10) to at least one hydraulic sub-consumer (N), the supply line (10) branching off from the main line (1) characterised in that the solenoid valve assembly comprises two 2/2 multi-way solenoid seat valves (V1, V2) switched in series within the main line (1) between the supply line (10) and the hydromotor (H), among which two 2/2 multi-way solenoid seat valves (V1, V2) one (V1) is actuable by a proportional solenoid (12) and is operable to achieve a blocking position (14) which is leakage free tight in flow direction towards the pump (3), and the other (V) is actuable by a black/white solenoid (15) and is operable to achieve blocking positions (16) which are leakage free tight in both flow directions, and that a branch line (Z) leads between the 2/2 multi-way solenoid seat valves (V1, V2) from the main line (1) at least to a pilot control port (21, 25) of at least one pressure compensator (D1, D, D2, D3), which pressure compensator controls directly or indirectly the pressure in the supply line (10) and/or the energy recovery depending on the pressure present between the two 2/2-multi way solenoid seat valves.
2. Electro-hydraulic lifting module according to claim 1, characterised in that the other (V2) of the two 2/2-multi-way solenoid seat valves having the black/white switching solenoid (15) is arranged in flow direction towards the hydromotor (H) upstream of the one 2/2 multi-way solenoid seat valve (V1) having the proportional solenoid (12) and is actuable magnetically as a redundancy safety device for the one 2/2 multi-way solenoid seat valve (V1).
3. Electro-hydraulic lifting module according to claim 1, characterised in that the two 2/2 multi-way solenoid seat valves (V1, V2) respectively include a pilot pressure control (13).
4. Electro-hydraulic lifting module according to claim 1, characterised in that the branch line (Z) either comprises a pilot control line (18) or a working pressure medium line (26) including a pilot pressure control line (29).
5. Electro-hydraulic lifting module according to at least one of the preceding claims, characterised in that the pump (3) is a dual quadrant pump (4) which is supplied during the energy recovery mode either directly from the main line (1) or from an extension line (27) of the branch line (Z) connected with the main line (1).
6. Electro-hydraulic lifting module according to at least one of claims 1 to 4, characterised in that the pump (3) is a single quadrant pump (38) which is supplied during the energy recovery mode from the extension line (27) of the branch line (Z) at a sucking side isolated from a tank (R) by a check valve (39).
7. Electro-hydraulic lifting module according to claim 5, characterised in that in the case of a dual quadrant pump (4) the branch line (Z) is connected with the closing pilot control port (21) of the pressure compensator (D) arranged in the supply line (10), wherein the pressure compensator (D) is actuable at an opening pilot control port (22) by control pressure from the main line (1).
8. Electro-hydraulic lifting module according to claim 5 or 7, characterised in that the electro-hydraulic lifting module (M) includes a load pressure signal circuit (LS) which can be supplied from the branch line (Z) and from the sub-consumer (N), and that a further pressure compensator (D1) is arranged in a connection line (36') leading from the supply line (10) to the tank (R), wherein the closing pilot control port (25) of the further pressure compensator (D1) is actuable with control pressure respectively also from the branch line (Z), while the opening pilot control port is actuable with control pressure from the supply line (10).
9. Electro-hydraulic lifting module according to claim 5, characterised in that the pressure compensator (D2) is arranged between the branch line (Z) and the extension line (27) and is actuable at the opening pilot control port from the branch line (Z) with pilot control pressure, wherein the closing pilot control port of the pressure compensator (D2) is actuable with control pressure from the main line (1), and that, preferably, the supply line (10) is connected with the main line (1) via a pilot pressure controlled 3/2 multi-way priority valve (P) arranged in the main line (1).
10. Electro-hydraulic lifting module according to claim 5, characterised in that the pressure compensator (D2) is arranged between the branch line (Z) and the extension line (27) and is actuable at the opening pilot control port with pilot pressure from the branch line (Z), wherein the closing pilot control port of the pressure compensator (D2) is actuable with control pressure from the main line (1), and that a further pressure compensator (3) is arranged in a connection line (36) extending from the main line (1) to the tank (R), the opening pilot control port of which is actuable with pilot control pressure from the branch line (Z) and the closing pilot control port of which is actuable with pilot from the main line (1), respectively.
11. Electro-hydraulic lifting module according to claim 6, characterised in that in the case of a single quadrant pump (38) the pressure compensator (D2) is arranged between the branch line (Z) and the extension line (27), that the opening pilot control port of the pressure compensator (D2) is actuable with pilot pressure from the branch line (Z), wherein the closing pilot control port of the pressure compensator (D2) is actuable with control pressure from the main line (1), and that, preferably, the supply line (10) is connected with the main line by pilot pressure controlled 3/2 multi-way priority valve (P) arranged in the main line (1).
12. Electro-hydraulic lifting module according to claim 11, characterised in that in addition to the pressure compensator (D2) a further pressure compensator (D3) is arranged between the branch line (Z) and the extension line (27) in a connecting line (36) extending from the main line (1) towards the tank (R), the opening pilot control port of which further pressure compensator (D3) is actuable with pilot control pressure from the branch line (Z) and the closing pilot control port of which is actuable with pilot control pressure from the main line (1).
13. Electro-hydraulic lifting module according to claim 9 or 11, characterised in that the 3/2 multi-way priority valve (P) is actuable at a closing pilot control port for isolating the supply line (10) from the main line (1) via an aperture (34) with control pressure from the branch line (Z), and is actuable with control pressure from the main line (1) at an opening pilot control port.
14. Electro-hydraulic lifting module according to claim 12, characterised in that the opening pilot control ports of the pressure compensator (D2) arranged between the branch line (Z) and the extension line (27) and of the further pressure compensator (D3) arranged in the connecting line (36) between the main line (1) and the tank (R) are connected respectively directly via a control line (29) to the branch line (Z), and that the closing pilot control ports of the pressure compensator (D2) and of the 3/2 multi-way priority valve (P) are connected respectively via a pilot control line (29) with the branch line (Z), the pilot control line (29) containing an aperture (34, 41).

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