EP2825778B1 - Device with hydrauliksystem for controlling at least a first and a second hydraulic consumer. - Google Patents

Description

The invention relates to a hydraulic system according to the feature configuration of the preamble of claim 1.

Such a device is used, for example, in machines such as loaders, for moving loads and serves to control actuators with working cylinders, in which pistons are moved or moved in accordance with a movement of the load to be moved. Depending on the positions of the pistons or actuators and the load moved by them, tilting of the machine may occur in the event of unfavorable center of gravity displacement, which is why it must comply in particular with the safety regulations specified in the safety standard EN 15000. Accordingly, at the risk of tipping a Lastmomentvergrößernde movement to prevent and allow a load torque-reducing movement. During operation of the machine, in the event of a sudden switch-off of the loads, in particular due to a strong braking acceleration, the machine may also tilt. This problem has hitherto been counteracted by the fact that the permissible travel speed for reducing the braking acceleration is reduced, wherein expediently the travel speed is proportional to the actuator position and delayed to the load, in other words, the movement is slowed down. This contradicts the user-side requirement of fast loading and unloading cycles. Alternatively, the movements of both actuators may be positively coupled such that undesired actuator positions are avoided.

Furthermore, it is desirable to allow uniform, "jerk-free" working at the limits of the range of movement of the machine, in other words when achieving the extreme positions of the actuators. For example, the flow divider designed for a certain volume range can be leaking, in that a fluid leakage current flows from an actuator assigned to a vertical movement and acted on by a vertical movement to an actuator assigned to a vertical movement and acted upon by a lower pressure, and the position of the further actuator in FIG Form of an irregularity in the movement, such as a "jerk", can affect noticeably. This situation occurs in particular when the horizontally movable actuator is retracted far and the vertically movable actuator is far extended. The known devices for controlling hydraulic consumers, such as the actuators, do not reliably prevent the fluid leakage current in this situation.

By the US 5,473,828 A a device for controlling at least two hydraulic consumers is known, each formed as a hydraulic cylinder, different extent of cylinder housings extendable piston rod drives for the purpose of driving two equally trained blade halves of an excavator. Due to the different travel lengths of the piston rod drives, it is possible, with the blade assembly closed and penetrating into an earth mass, to break it out of the other ground surface for lifting, wherein the closed excavator bucket is tilted by the longer working cylinder executes the pertinent tilting movement.

In order to hold the blade halves in the closed position in this tilting or Ausbrechbewegung, a control line is provided downstream of the Stromteilerpfad that supplies the working cylinder with the lower extension length, after a flow divider that supplies the two sides of the piston with hydraulic fluid a 3/2-way valve controls such that with increasing pressure when breaking the soil of this valve reaches its closed position, so that a further influx of working fluid is suppressed to this hydraulic cylinder and this is held without overload in its shovel closing position.

By the DE 11 2005 001 879 T5 For example, a fluid pressure actuator control system is known for controlling an adjustment of a predetermined fluid pressure actuator of at least two fluid pressure actuators as hydraulic consumers to which flows of pressurized fluid delivered from a common fluid pressure source may be individually allocated via a flow divider. In the context of this individual allocation, each hydraulic consumer is assigned an independent locking device which can be actuated by a central control device, operating states at the respective hydraulic consumers being monitored by a comprehensive sensor system and causing the control device to supply fluid quantities via the respective blocking device in the form of valves Consumers supply or from these again preferably in a tank. Because of this separate control concerning the respective hydraulic consumers, it is possible with this known solution, on the one hand a fine adjustment or fine positioning for the hydraulic consumers, for example in the form of hydraulic actuators to make and further created in such a way, the position or location of a Working equipment, for example in the form of a bucket automatically according to the position of a respective other movable element, for example in Shape of a hydraulically operated lifting arm to adapt. The solution known to that effect is structurally complex and reliable control of fluid leakage flows in the frame mentioned above is not possible with this known solution.

The JP S58-180898 describes a hydraulic system comprising at least one first hydraulic consumer and at least one second hydraulic consumer and a control device for controlling the hydraulic consumers, wherein the first and the second hydraulic consumer is a fluid-actuated actuator with two separate actuator sides, which are responsible for a movement of a respective piston The control device for controlling at least one first hydraulic consumer and at least one second hydraulic consumer comprises a flow divider, a blocking device and the respectively desired fluid supply of the hydraulic consumers, a first directional control valve and a second directional control valve, wherein the hydraulic consumers at least one of the flow divider for dividing a coming from a pressure fluid supply fluid supply in predetermined, the respective hydraulic Verbr einer leading partial flows can be supplied with fluid with specifiable pressure, wherein by means of at least one of the flow divider and at least one hydraulic consumer arranged controllable blocking device, a fluid flow from that hydraulic consumer with higher pressure on the flow divider to that hydraulic consumer with lower pressure is suppressed, and wherein the at least one barrier means is arranged in fluid communication from the flow divider to the hydraulic consumer with lower pressurization, wherein a control line from the leading from the hydraulic consumer with each higher pressurization to the flow divider fluid connection is guided to the locking device such that the higher pressurization activates the locking device in the direction of its blocking position, so that in any pressure situation of the controlled hydraulic consumer in the fluid connection from the hydraulic consumer with higher pressure to the flow divider pending fluid pressure hydraulic consumers with lower pressure not achieved and consequently not actuated in an unintentional manner, and wherein the respective desired fluid supply of the hydraulic consumers, a first valve and a second valve are provided.

Based on this prior art, the invention has the object to prevent a fluid leakage flow between two powered by a flow divider with fluid, acted upon by different pressures, double-acting hydraulic consumers in a simple and reliable manner.

This object is achieved by a hydraulic system according to the feature configuration of claim 1.

The hydraulic system according to the invention is characterized in that the second valve is connected between the pressure supply and the two hydraulic consumers such that the second valve is connected directly to an extension side of the second hydraulic consumer and via the flow divider to both retraction sides of the two hydraulic consumers.

It is further provided that a control line is guided by the leading from the hydraulic consumer with each higher pressurization to the flow divider fluid connection to the locking device, that the higher pressurization controls the locking device in the direction of its blocking position, so that in any pressure situation of the controlled hydraulic consumers in the fluid connection from the hydraulic consumer with higher pressure to the flow divider pending fluid pressure does not reach the hydraulic consumer with lower pressurization and consequently not operated in an unintentional manner.

A fluid pressure present in the corresponding fluid connection maximally reaches the blocking device, which blocks a further fluid path to the respective other hydraulic consumer.

Advantageously, during operation of the device, the at least one, preferably designed as a valve, particularly preferably as a check valve, designed locking device driven by the flow divider fluid pressure and blocked by the originating from the hydraulic consumer with each higher pressurization fluid pressure. In this advantageous embodiment of the invention, it is ensured that the at least one blocking device is blocked on the occurrence of a fluid leakage current at the flow divider. In an embodiment of the locking device as a lockable non-return valve, this can be advantageously closed by the control line, wherein the line for controlling the locking device is connected in an advantageous manner fluid leading to the fluid connection from the hydraulic consumer with higher pressure to the flow divider.

It is further conceivable that fluid pressures occur in both fluid directions between the interconnected via the flow divider hydraulic consumers, which are alternately acted upon with higher and lower pressure. Here are expediently two, the respective fluid direction associated, provided in the fluid connection from the flow divider to the respective hydraulic consumer with lower pressurization locking devices are provided. However, it is also conceivable according to the invention, an effective in both fluid directions, corresponding Form fluid flow preventing locking device. With the help of the device according to the invention, even in special positions of the hydraulic consumers without disturbances by fluid flows without interference ("jerk-free") and work safely, the solution according to the invention can also be implemented particularly cost. Former possibly via the flow divider leading leakage currents are thus avoided with certainty.

In order to realize these aforementioned advantageous solutions, it can be further provided in a preferred manner that the control line between a junction of the locking device for locking the same and a branch point extends, opens in both a coming from the output of a current divider path of the flow divider fluid line and the further fluid line, which leads in the direction of the consumer with the higher pressurization or is connected to carry fluid to this consumer.

The invention further relates to a hydraulic system comprising at least one first hydraulic consumer and at least one second hydraulic consumer and a device according to the invention for controlling the hydraulic consumers. The device according to the invention can be manufactured as a tradable unit, independent of the hydraulic consumers and a pressure supply, distributed and used in a hydraulic system.

For use of the hydraulic system in a machine for moving loads, the first and / or the second hydraulic load can be fluid-actuated actuators, each with two separate actuator sides, which can be alternately fluid-conductively connected to the pressure supply for movement of the respective actuator. According to the pressurization of the respective actuator side, the actuator and the load connected thereto are moved. Preferably, the Actuators each one in a working cylinder retractable and guided pistons, expediently associated with a retracting movement of the respective piston actuator sides are connected to the flow divider. However, alternatively, an extending movement of the respective piston associated actuator sides may be connected to the flow divider. In this way, a synchronization, in other words a coordinated movement, both pistons and actuators guaranteed, either in the respective retraction direction or in the respective extension direction. Also combinations of coupled retraction and extension movements are conceivable.

In a further preferred embodiment of the hydraulic system according to the invention, one of the actuators comprises a telescopic cylinder with a piston preferably retractable and extendable in a horizontal direction and a further actuator comprising a lifting cylinder with a further piston which can be retracted and retracted therein in a vertical direction Locking device between the flow divider and the lifting cylinder is arranged. Here, the total movement caused by the actuators is divided into a preferably horizontally directed component of movement and another preferably directed in the vertical direction of movement component and correspondingly changeable via the telescopic cylinder or the lifting cylinder. By the inventive arrangement of the locking device between the flow divider and the lifting cylinder and locking the corresponding fluid connection is prevented during operation of the hydraulic system that at a designed, for example, 150 l / min flow divider and a pressure of 150 bar in the telescopic cylinder, a fluid leakage current of approx 5 l / min reaches the lifting cylinder.

Further advantages and features of the invention will become apparent from the figures and the following description of the drawing.

Fig. 1 bis 3

jeweils einen Schaltplan eines mit einer erfindungsgemäßen Vorrichtung zur Ansteuerung von hydraulischen Verbrauchern ausgestatteten Hydrauliksystems.

The features shown in the figures are purely schematic and not to scale. It shows:

Fig. 1 to 3

in each case a circuit diagram of a hydraulic system equipped with a device according to the invention for controlling hydraulic consumers.

One in the Fig. 1 to 3 each shown hydraulic system comprises a first hydraulic consumer 10, which is designed as an actuator with a working cylinder, more precisely a telescopic cylinder, and a second hydraulic consumer 12, which is also designed as an actuator with a working cylinder, more precisely a lifting cylinder. In the two designed as actuators hydraulic loads 10, 12, respectively, a first piston 14 and a second piston 16 is movably guided, wherein the first piston 14 in a horizontal direction H in the corresponding working cylinder and retractable and the second piston 16 in a vertical direction V in the corresponding working cylinder and retractable.

For adjusting the position of the respective piston 14, 16 or for a corresponding actuator movement, a retraction side 18.1, 18.2 or an extension side 20.1, 20.2 of the corresponding working cylinder is fluid-connected to a pressure supply P and pressurized with fluid with a presettable pressure. Fluid is conveyed by means of an actuatable pump 30 from the pressure supply P to the entry side 18.1, 18.2 or to the extension side 20.1, 20.2 of the respective hydraulic consumer 10, 12. In a movement of the respective piston 14, 16 on the retraction side 18.1, 18.2 or the extension side 20.1, 20.2 displaced fluid can be performed via a tank connection T back into the tank or a reservoir. With the in the Fig. 1 to 3 shown hydraulic system is the Superimposition of a lifting movement in the vertical direction V with a translational or telescopic movement in the horizontal direction H possible.

For each desired fluid supply of the hydraulic consumers 10, 12 are designed as electromagnetically actuated 4/3-way valve formed first valve 22 and designed as an actuatable 4/3-way valve second valve 24. The switchable between an ON position (left) for pressurizing the Einfahrseite 18.1 of the first hydraulic consumer 10, a NEUTRAL position (center) to complete all fluid connections and an OFF position (right) for pressurizing the Ausfahrseite 20.1 of the first hydraulic consumer 10 first valve 22 is connected directly between the pressure supply P and the first hydraulic consumer 10. The second valve 24, which between an ON position (left) for pressurizing a Einfahrseite 18.2 of the second hydraulic consumer 12, a NEUTRAL position (center) to complete all fluid connections and an OFF position (right) for pressurizing a Ausfahrseite 20.2 of second hydraulic consumer 12 is switched, is so connected between the pressure supply P and the two hydraulic consumers 10, 12, that the second valve 24 directly to the extension side 20.2 of the second hydraulic consumer 12 and both Einfahrseiten 18.1, 18.2 of the two hydraulic consumers 10th , 12 is connected.

For dividing a from the pressure supply P via the second valve 24 to the Einfahrseiten 18.1, 18.2 of the hydraulic load 10, 12 guided fluid flow into corresponding partial flows, a flow divider 26 is provided. The flow divider 26 has a first throttle 28. 1 and a second throttle 28. 2 which supply the 100% amount of fluid flow coming from the pressure supply P into a first partial flow leading to the first hydraulic consumer 10, for example 67% and leading to the second hydraulic consumer 12 Example, divides 33% amount of second fluid flow. It is understood that instead this fixed predetermined ratio between the first and second partial flow, the two throttles 28.1, 28.2 can be individually designed differently adjustable. The flow divider 26 is designed for a volume flow range of, for example, 150 l / min. Here, a compromise between the minimum volume flow, in which the flow divider 26 fulfills its function, and a pressure drop via a second switching valve 34.2 to find at maximum flow. At low flow rate of coming from the pressure supply P fluid flow of the flow divider 26 operates according to the two throttles 28.1, 28.2.

In a first fluid connection or fluid line F1 from the flow divider 26 to the first hydraulic consumer 10, a check valve 36 is provided, which closes at a pressure supply to the Einfahrseite 18.1 of the first hydraulic consumer 10 via the first valve 22 to avoid a pressure drop across the first fluid connection F1 , In a second fluid connection or fluid line F2 from the flow divider 26 to the second hydraulic consumer 12, a locking device 38 is provided, which is designed as a check valve and via a fluid leading to the first fluid connection F1 connected, designed as a leakage current line control line S is lockable.

The fluid and pressure-carrying control line S (drawn in dashed lines) runs between a connection point AS of the blocking device 38 for blocking the same and a branch point AB, into which both one of the output A1 of a current divider path ST1 of the flow divider 26 coming fluid line F1 'opens as well as the other Fluid line F1, which opens in the direction of the consumer 10 with the higher pressurization. The current divider path ST2 of the current divider 26 is connected via the output A2 of the current divider 26 to the fluid line F2 ', which further leads to an input-side connection of the blocking device 38. The junction AS and the leading to the consumer 12 fluid line or Connection F2 are connected to the output side of the check valve 38, the blocking member opens in the direction of said output side at queuing a corresponding fluid pressure and otherwise can remain under inclusion of the differential pressure between input and output side of the check valve 38 in a closed position.

The flow divider 26 and the locking device 38 are part of a device 32 for controlling the two hydraulic consumers 10, 12, wherein the device 32 further comprises the check valve 36 and switchable valves 34.1, 34.2, 34.3. A first switchable valve 34.1 is arranged in the first fluid connection F1 from the flow divider 26 to the entry side 18.1 of the first hydraulic consumer 10. A second switchable valve 34.2 is arranged to bypass the flow divider 26 together with the barrier means 38 at an immediate pressurization of the pressure supply P via the second valve 24 to the retraction side 18.2 of the second hydraulic consumer 12. A third switchable valve 34.3 is arranged in a direct return line from the extension side 20.1 of the first hydraulic consumer 10 to the tank port T, that is, parallel to the first valve 22.

Fig. 2 differs from Fig. 1 in that the second valve 24 shown on the right is in the ON position and accordingly via the flow divider 26, the Einfahrseiten 18.1, 18.2 of the two hydraulic consumers 10, 12 are pressurized and the respective pistons 14, 16 a horizontal first retraction E1 or perform a vertical second retraction E2. By the current divider 26 through the fluid connections F1, F2 to Einfahrseite 18.1, 18.2 of the respective hydraulic consumer 10, 12 partial flows are forcibly coupled and the pistons 14, 16 move according to the flow divider 26, more precisely on the throttles 28.1, 28.2, set partial flows as well as the given on the respective retraction side 18.1, 18.2 Partial volume of the respective working cylinder in a predetermined ratio to each other. When using the hydraulic system in a machine, such as a Telelader, for moving loads moves through this forced coupling of the first piston 14 and actuator in a lowering movement according to the second retraction E2 of the second piston 16 and actuator according to the first retraction E1 a. As a result, tilting of the machine is effectively avoided by an unfavorable center of gravity displacement. The displaced by the movement of the pistons 14, 16 on the extension side 20.1, 20.2 of the respective hydraulic consumer 10, 12 fluid is passed through the tank port T back into the tank.

Fig. 3 differs from Fig. 1 in that the first valve 22 shown on the left is in the ON position and accordingly the retraction side 18.1 of the first hydraulic consumer 10 is pressurized and the first piston 14 performs a retraction movement E1 pointing to the right in the figure. Due to the NEUTRAL position of the second valve 24 is in the second fluid connection F2 and the flow divider 26 of the prevailing on the retraction side 18.2 of the second piston 16 pressure. In the in Fig. 3 illustrated situation, the second piston 16 is extended far out of the working cylinder of the second hydraulic consumer 12, so that at the corresponding retraction side 18.2 a low pressure is present. This low pressure is also at the power splitter side of the check valve 36 in the first fluid connection F1. The said check valve 36 is closed due to the actuator side, much higher pressure from the pressure supply P.

At the first hydraulic consumer 10 associated side of the flow divider 26 and pending in the corresponding portion of the first fluid connection F1 fluid pressure can flow through the flow divider 26 almost unhindered and would reach without the locking device 38, the retraction 18.2 of the second hydraulic consumer 12 and the position of the second Piston 16 in an undesirable manner, in particular "jerky", can influence. By means of the blocking device 38, such undesired influence is prevented by the blocking device 38 being actuated and closed by the fluid pressure present in the first fluid connection F1 via the control line S before such a fluid flow via the flow divider 26 causes the second fluid connection leading to the second hydraulic consumer 12 F2 reached.

As soon as the pressure applied to the retraction side 18.1 of the first hydraulic consumer 10 is reduced and / or the switching position of the first valve 22 is changed, fluid leakage flows are reduced via the flow divider 26 and negligibly small or completely prevented at the latest at a pressure drop at the flow divider 26. As a result, the locking device 38 is unlocked again and the retraction 18.2 of the second hydraulic consumer 12 can again on the in Fig. 2 shown position of the second valve 24 are pressurized. In the embodiment of the device 32 according to the invention is achieved in particular that a trouble-free working ensured even in special situations of a hydraulic system and thus fast charging cycles are possible.

Claims (5)

1. A hydraulic system comprising at least one first hydraulic consumer (10) and at least one second hydraulic consumer (12) and a control device (32) for actuating the hydraulic consumers (10, 12),

   - wherein the first (10) and the second hydraulic consumer (12) is a fluid-actuated actuator each with two actuator sides (18.1, 20.1; 18.2, 20.2) which are separated from one another, which actuator sides can be connected in an alternating manner to the pressure supply (P) for a movement (E1, E2) of a respective piston (14, 16) to guide fluid,

   - wherein the control device (32) comprises a flow divider (26), a shut-off device (38) and, for the desired fluid supply of each of the hydraulic consumers (10, 12), a first way valve (22) and a second way valve (24),

   - wherein the hydraulic consumers (10, 12) can be supplied with fluid at a predefinable pressure at least via the flow divider (26) for dividing a fluid flow coming from a pressure supply (P) in predefinable partial flows, which leads to the respective hydraulic consumer (10, 12),

   - wherein a fluid flow from the respective hydraulic consumer (10) with higher pressure loading via the flow divider (26) to the respective hydraulic consumer (12) with lower pressure loading can be suppressed by means of the actuatable shut-off device (38) arranged between the flow divider (26) and at least one hydraulic consumer (12),

   - wherein the at least one shut-off device (38) is arranged in a fluid connection (F2) from the flow divider (26) to the hydraulic consumer (12) with lower pressure loading,

   - wherein a control line (S) is guided from the fluid connection (F1) running from the hydraulic consumer (10) which has the higher pressure loading to the flow divider (26) to the shut-off device (38) such that the higher pressure loading actuates the shut-off device (38) in the direction of the blocking position thereof, with the result that, in the respective pressure situation of the actuated hydraulic consumer (10, 12), a fluid pressure which is present in the fluid connection (F1) from the hydraulic consumer (10) with higher pressure loading to the flow divider (26) does not reach the hydraulic consumer (12) with lower pressure loading, and consequently does not actuate this consumer in an unintended manner,

   - characterised in that the second valve (24) is switched between the pressure supply (P) and the two hydraulic consumers (10, 12) such that the second valve (24) is connected directly to a retraction side (20.2) of the second hydraulic consumer (12) and, via the flow divider (26), to both extension sides (18.1, 18.2) of the two hydraulic consumers (10,12).
2. The hydraulic system according to claim 1, characterised in that during the operation thereof, the at least one shut-off device (38), which is preferably designed as a valve, particularly preferably, as a non-return valve, is actuated by the fluid pressure flowing through the flow divider (26) and can be blocked by the fluid pressure originating from the hydraulic consumer (10) with a respective higher pressure loading.
3. The hydraulic system according to claim 1 or 2, characterised in that the control line (S) runs between a connection point (AS) of the shut-off device (38) for blocking said connection point and a branching point (AB), into which control line both a fluid line (F1"), coming from the outlet (A1) of a flow divider pathway (ST1) of the flow divider (26), discharges, as does the further fluid line (F1), which runs in the direction of the consumer (10) with the higher pressure loading.
4. The hydraulic system according to one of the preceding claims, characterised in that the pistons (14, 16) are each guided in a working cylinder such that said pistons can be extended and retracted, and in that the actuator sides (18.1, 18.2) allocated to a retracting movement (E1, E2) of the respective piston (14, 16) are connected to the flow divider (26).
5. The hydraulic system according to one of the preceding claims, characterised in that one of the pistons (14) is guided such that it can be extended and retracted in a telescopic cylinder, preferably in a horizontal direction (H), that an additional piston (16) is guided such that it can be extended and retracted in a lifting cylinder, preferably in a vertical direction (V), and in that the shut-off device (38) is arranged between the flow divider (26) and the lifting cylinder.

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