DE102019129300A1 - Power machine with a frame and a pivotable boom - Google Patents

Abstract

An engine, in particular a motor vehicle, is provided with a frame and a boom that can be pivoted about a first pivot axis with respect to the frame, a tilting lift cylinder being provided for tilting / pivoting a load-bearing device with respect to the boom, a compensation lifting cylinder being arranged between the boom and the frame is, wherein at least one tilt actuation unit is provided for actuating and / or pressurizing the tilting lift cylinder, wherein at least one pivoting actuation unit is provided for actuating and / or pressurizing the pivoting lift cylinder, a first connecting line and a second connecting line being provided between the tilting lift cylinder and the compensation lift cylinder, wherein the first connecting line comprises at least one first controllable actuator, at least one first control line for controlling / actuating the first controllable actuator between the first actuator and d he second connecting line is provided, which is characterized in that at least one second control line is provided for controlling / actuating the first actuator and / or that at least the first connecting line comprises at least one second, controllable actuator.

Description

The invention relates to an engine, in particular a motor vehicle, with a frame and a boom that can be pivoted about a first pivot axis with respect to the frame according to the preamble of claim 1.

State of the art

Telescopic handlers have been in use for years, e.g. in civil engineering, in recycling and waste management, in gardening and landscaping as well as in agriculture. In addition to the standard attachments or tools such as shovel and fork, other tools such as load hooks, concrete buckets, sweeping machines, work platforms, winches and grabs can also be used. There are quick-release plates for quick tool changes.

Loading systems of telescopic handlers usually have a lifting arm with at least one extension stage, which is usually pivotably mounted on the rear of the vehicle. The lifting movement is carried out by a lifting cylinder that is controlled or actuated by the driver using a directional valve. A seat-tight load-holding valve is installed directly on the lifting cylinder and secures the load against uncontrolled lowering due to leaks at the directional control valve or in the event of a line break. During an intended lowering movement, the load-holding valve is controlled by building up pressure.

The inclination of the tool carrier or a load pick-up is varied by means of a tilt cylinder. Like the lifting cylinder, the tilting cylinder is operated by the driver or supplied with hydraulic energy via a directional control valve and the load is secured by a load-holding valve.

During the lifting movement, the tool carrier is pivoted on a circular path around the pivot point of the lifting arm. A compensation cylinder is attached to the lifting arm in order to compensate for the angular change in the tool alignment. This cylinder is pulled apart during the lifting movement. The amount of oil displaced in the process is fed to the tilt cylinder, whereby its spatial orientation or that of the tool is kept approximately constant.

The disadvantage here, however, is that the mechanical coupling of the lifting cylinder and the compensation cylinder by means of the lifting arm influences the lifting cylinder or the other hydraulic circuit or the pressure conditions of the lifting cylinder are changed if the tool carrier is tilted, for example. Under certain conditions, the lifting arm could even be raised in an uncontrolled manner, which represents a safety risk. When the lifting arm is pivoted by means of the lifting cylinder, the compensation cylinder or the pressure conditions of the circuit with the tilt cylinder and the compensation cylinder can also be influenced or changed.

For safety and hydraulic reasons, for example, an overridable differential pressure control valve is arranged between the directional control valve for actuating the tilt cylinder and the compensation cylinder in order to eliminate the corresponding risks.

Object and advantages of the invention

In contrast, the object of the invention is to propose an engine, in particular a motor vehicle, which realizes an improved or more efficient mode of operation compared to the prior art, in particular has an improved pressurization or energy utilization of the hydraulic system.

Based on an engine, in particular a motor vehicle, of the type mentioned in the introduction, this object is achieved by the features of claim 1. Advantageous embodiments and developments of the invention are possible through the measures mentioned in the subclaims.

Accordingly, an engine according to the invention, in particular a motor vehicle, is characterized in that at least one second control line is provided for controlling / actuating the first actuator and / or that at least the first connecting line comprises at least one second, controllable actuator.

With the help of this measure or measures it is achieved that in addition to the (passive) mechanical coupling of the hydraulic tilt compensation system with the hydraulic lifting system by means of the lifting arm, there is also an (active) separate control or control / actuation of the hydraulic tilting Compensation system is realizable. In this way, under certain prerequisites or operating conditions, the hydraulic tilt compensation system can be influenced or controlled / monitored in an advantageous manner. For example, the first actuator and / or the first connecting line can be opened directly by means of the second control line and / or by means of the second, controllable actuator in addition to the previous control options, or the flow of the hydraulic fluid / oil can be activated. In this way, disadvantageous pressure changes or a disadvantageous pressure increase in the hydraulic lifting system or the lifting cylinder circuit can be effectively prevented or limited.

Accordingly, the invention opens up a wide variety of control options, so that the power machine or the boom / lifting arm can be operated in a more flexible and optimized manner. In this way, high safety requirements can be met and the hydraulic system (s) can also be improved. For example, according to the invention, the first connecting line or the first actuator can already be opened / released or actuated / controlled before or at the start of the actuation of the lifting cylinder, so that no disadvantageous pressure conditions in the hydraulic tilt compensation system and / or hydraulic lifting System are in place.

Thus, according to the invention, an advantageous increase in the payload can be achieved, since pressure losses or pressure-reducing effects of the previous controls can be reduced or avoided. For example, the first connection line can be "activated" before or at the same time as the lifting cylinder is applied, so that in certain operating conditions the compensation cylinder is no longer adjusted by means of the lifting cylinder, but rather the compensation cylinder is freely moving or even subjected to hydraulic pressure and thus supports the lifting movement of the boom. In first tests, the invention was able to determine a 10 to 15% increase in the payload. The second control line is advantageously arranged between the swivel actuation unit and the first actuator. This ensures that the first actuator is advantageously activated or actuated immediately upon actuation of the pivot actuation unit or the lift valve by the operator. This can not only be implemented structurally or in terms of circuitry without great effort, but also has a high level of operational reliability.

Alternatively or in combination with the variant with the second control line, it is advantageous to arrange the second, controllable actuator hydraulically parallel to the first, controllable actuator, with the first, controllable actuator and the second, controllable actuator between a first branch point and a second branch point of the first Connecting line are arranged. In this way, the second, controllable actuator can be actuated / controlled separately or independently / in addition to the first, controllable actuator, so that the first connecting line can advantageously be opened or switched free. With this, too, the first connection line can be “switched free”, either before or at the same time as the actuation of the lifting cylinder.

An (electrical and / or electronic) actuation sensor is advantageously provided for detecting the actuation / adjustment of the lifting cylinder and / or the swivel actuation unit / valve and / or the boom. The actuation sensor is preferably arranged on the swivel actuation unit and / or on the lifting cylinder and / or on the boom. This can be used to generate an advantageous (electrical) (control) signal that is transmitted to / for the first / second actuator, for example, by means of an electrical line or wirelessly by means of a transmitter and receiver. As a result, an opening or activation of the first connecting line according to the invention can also be realized in this way in an advantageous manner.

Advantageously, the first connecting line comprises at least one first load holding unit and / or a first load holding valve, with at least one third control line preferably being provided between the second connecting line and the first load holding unit and / or the first load holding valve. This ensures that the (double-acting) lifting cylinder (s) used are protected against uncontrolled and impermissible pressures. In addition, the fluid flow or the oil column is prevented from tearing off. Furthermore, the inadmissible lowering of the load in the holding position is prevented. A pipe rupture safety device is integrated through the check valves in the load holding valves. This prevents the load from lowering if a hose line or a hydraulic pipeline bursts or tears. These components or valves must therefore be installed directly on the lifting cylinder. Through the control line provided, the load-holding valve opens proportionally until the pressure conditions are balanced.

In a particular development of the invention, at least one second load holding unit and / or a second load holding valve is arranged and / or comprised between the tilt actuation unit and the tilt stroke cylinder and / or the compensation stroke cylinder and / or the first, controllable actuator and / or the second, controllable actuator the second connecting line at least one second differential pressure control unit and / or a second differential pressure control valve, wherein the second load holding unit is preferably designed as a check valve arrangement and / or comprises at least two second load holding valves. This ensures that the tilting or tilting cylinder circuit is pretensioned. Because of this bias, the load-holding unit or the load-holding valve is held in its open switching position. Thus, the transfer of the load pressure from the piston side of the tilting or tilting lift cylinder is not prevented by the load holding valve before the start of the lifting movement of the swing lift cylinder. This ensures safe operation.

In an advantageous embodiment of the invention, the first controllable actuator is designed as a first differential pressure control unit and / or first differential pressure control valve and / or first pressure limiting unit and / or first pressure limiting valve and / or pressure reducing valve. In this way, the pressure that is built up at the connection of the tilt actuation unit can be reduced in an advantageous manner, down to a value that is low enough that the unloaded loading system cannot be lifted by the compensation lift cylinder alone. If the compensation stroke cylinder is pulled apart by an active stroke movement by the tilt stroke cylinder, hydraulic fluid / oil is displaced via the rod side of the compensation stroke cylinder. The pressure that is built up starting from the connection of the cylinder controls both the load holding valve and the differential pressure control valve. During an active lifting movement, starting from the loading installation, an unimpeded volume compensation between the tilting lift cylinder and the compensation lift cylinder is thus made possible according to the invention.

At least one third load holding unit and / or a third load holding valve is advantageously arranged between the swivel actuation unit and the swivel lift cylinder. In this way, the swivel stroke cylinder can also be secured in an advantageous manner against impermissible lowering in the event of damage or a line break in the swivel stroke cylinder circuit.

Figure list

An embodiment of the invention is shown in the drawing and will be explained in more detail below with reference to the figures.

• 1 ein erster, schematischer Hydraulikschaltplan eines Teleskopladers und
• 2 ein zweiter, schematischer Hydraulikschaltplan eines Teleskopladers.

Specifically shows:

• 1 a first, schematic hydraulic circuit diagram of a telehandler and
• 2 a second, schematic hydraulic circuit diagram of a telehandler.

Two different hydraulic systems according to the invention of a telescopic handler are schematically shown in the figures 1 outlined. The telehandler 1 includes, inter alia, a boom 1.1 or a telescopic lifting arm 1.1 around a first pivot axis 1.8 with the help of a swivel cylinder 2.1 or lifting cylinder 2.1 in relation to a vehicle frame 1.6 is adjustable / pivotable. This allows the cantilever arm 1.1 can be adjusted in height. The length adjustment can be implemented in a known manner in one or more stages and is not shown or carried out here in more detail.

The telehandler 1 also has a driver's cab in a known manner 1.7 on, in which one or two or more control elements for driving and for operating the hydraulic system are present in an advantageous manner. In addition, wheels are provided in a known manner, which are preferably all drivable by means of a drive motor and / or steerable by the driver.

At the boom 1.1 or telescopic boom arm 1.1 is a load bearing 1.3 or tool carrier 1.3 pivotable about a second pivot axis 1.9 arranged pivotably. A burden 1.4 or a tool 1.4 is at one end of the arm 1.5 arranged, the tool carrier 1.3 with the help of a tilting cylinder 3.1 or tilt cylinder 3.1 in relation to the end of the arm 1.5 can be adjusted / pivoted.

The tilt cylinder 3.1 is with a compensation cylinder 4.1 via a first connection line I. and a second connection line II connected to each other hydraulically, ie that via the two connecting lines I. and II Hydraulic fluid / oil can be exchanged or these are integrated in a common hydraulic circuit.

In relation to the present invention, it is of interest, among other things, that when the tilt cylinder is extended to its mechanical end position without load, port 3.2 / B of an actuating valve 3.2 or directional valve 3.2 starting from the maximum possible working pressure impressed. Without a differential pressure control valve 4.2 this pressure would also be at port 4.1 / K of the compensation cylinder 4.1 stand up and apply a force to the lift arm 1.1 exercise that is large enough to fully lift the entire loading system without load. When the lifting movement is not actuated, ie no actuation of a swivel actuation valve 2.2 or lifting / directional valve 2.2 , the lifting cylinder works 2.1 against this movement, the loading system would be braced by the effective forces. This situation would be dangerous if the directional control valve 2.2 of the lifting cylinder 2.1 would be easily actuated in the stroke direction or other advantageous valves 5.1 and 5.2 a lift arm damping system 5.5 would be switched. In particular, the actuation of the valve 5.2 is critical. Since the lift cylinder 2.1 the force of the compensation cylinder 4.1 can no longer counteract this, the loading system would be raised in an uncontrolled manner, whereby on the piston side K of the lifting cylinder 2.1 a vacuum would be created.

In order to prevent this potential risk, according to the invention, between the directional control valve 3.2 and the compensation cylinder 4.1 advantageously an overridable differential pressure control valve 6.1 arranged. This valve 6.1 reduces the pressure at port 3.2 / B of the Directional control valve 3.2 is built up, except for a value that is low enough that the unloaded loading system is no longer solely due to the compensation cylinder 4.1 can be raised. The same protective function can also be achieved by an override pressure relief valve 6.1 can be achieved. The pressure relief valve 6.1 has a first control line III or first pilot line III to control or actuate it.

Becomes the compensation cylinder 4.1 by an active lifting movement by the lifting cylinder 2.1 pulled apart, it is over the rod side S of the compensation cylinder 4.1 Displaces oil. The pressure from port 4.1 / S of the cylinder 4.1 is built, controls both the load-holding valve 3.3 as well as the differential pressure control valve 6.1 on. During an active lifting movement, starting from the loading system, there is thus an unhindered volume equalization between the tilting cylinder 3.1 and the compensation cylinder 4.1 enables. A free lift arm movement with active lift arm damping is also made possible.

According to the invention comprises a valve unit 6th or valve block 6th in addition to the differential pressure control valve 6.1 further valves 6.2 , 6.3 , 6.4 and or 6.5 . About the pressure-reducing effect of the differential pressure control valve 6.1 Override according to the invention is targeted by a branch 6.2 or an advantageous shuttle valve 6.2 one, second control line IV or a second, so-called pilot signal at connection 6 / X1 of the valve unit 6th available. Connection 6 / X1 is with the pressure / working line from connection 2.2 / B of the lift or directional valve 2.2 for connection 2.3 / A of the load holding valve 2.3 on the lifting cylinder 2.1 connected in an advantageous manner. This is exactly when a signal pressure is applied to 6 / X1 of the valve unit 6th or the valve 6.1 built up when the machine operator uses the directional control valve 2.2 initiates a lifting movement. In this case there is a force effect of the compensation cylinder 4.1 desired or advantageous.

So that the load pressure from the tilt cylinder 3.1 is transmitted from, it is also advantageous that the load-holding valve 3.3 remains in its activated switching state as long as there is no line break. This is achieved in an advantageous manner in that the line circuit to the tilt cylinder 3.1 with the help of a check valve arrangement 6.3 or blocking block circuit 6.3 is pretensioned tightly. The preload pressure results from the fact that the (two) shut-off valves or load-holding valves are opened via the pressure in the respective opposite working line and should advantageously be higher than the necessary control pressure of the load-holding valve 3.3 .

In the event of a failure of the safety-critical line I. between connections 6 / A1 and 3.3 / A of the load holding valve 3.3 on the tilt cylinder 3.1 , the bias of the circuit cannot be maintained, so that the load-holding valve 3.3 immediately closes and the load on the tilt cylinder 3.1 keeps tight.

Another differential pressure control valve is used to ensure that the pre-tensioning of the tilt cylinder circuit is reliably maintained even after the cylinder has moved 6.4 advantageous. This ensures that the line II between 3.1 / S of the tilt cylinder 3.1 and 6 / B1 during tilting movements of the tool carrier 1.3 not completely via the directional control valve 3.2 is relieved towards the tank T. The load holding valve 3.3 the blocking function is opened by means of a fourth control line V during these movements, which is why it cannot maintain the pre-tension.

• - Durch die Sperrventilanordnung 6.3 sowie das Differenzdruckregelventil 6.4 wird eine vorteilhafte Vorspannung des Kippzylinderkreislaufes erreicht. Aufgrund dieser Vorspannung wird das Lasthalteventil 3.3 in seiner offenen Schaltstellung gehalten. Damit wird die Übertragung des Lastdruckes von der Kolbenseite K des Kippzylinders 3.1 vor Beginn der Hubbewegung nicht durch das Lasthalteventil 3.3 gehindert.
• - Um das Differenzdruckregelventil 6.1 aufzusteuern, ist zuvor keine Ausfahrbewegung des Kompensationszylinders 4.1 und damit auch kein Energieaustausch von der Hubsektion zur Kolbenseite K des Kompensationszylinders 4.1 nötig. Das Differenzdruckregelventil 6.1 wird anhand eines zusätzlichen Drucksignals bzw. der der zweiten Steuerleitung IV an Anschluss X1 des Ventilblocks 6 aufgesteuert.
• - Die hubunterstützende Kraftwirkung des Kompensationszylinders 4.1, unter Nutzung des auf der Kolbenseite K des Kippzylinders 3.1 wirkenden Lastdruckes, steht durch die beiden zuvor beschriebenen Merkmale in vorteilhafter Weise zur Verfügung, bereits bevor eine Hubbewegung des Hubarms 1.1 stattfindet.
• - Die hubunterstützende Funktion wird ab einem Lastdruck auf der Kolbenseite K des Hubzylinders 2.1 wirksam, der in vorteilhafter Weise hoch genug ist, das Differenzdruckregelventil 6.1 aufzusteuern. Abhängig vom Aufsteuerverhältnis des Differenzdruckregelventils 6.1 ist dieser Druck gering genug, dass die hubunterstützende Funktion der Schaltung über den gesamten Nutzlastbereich der Maschine wirksam ist.
• - Somit ergibt sich, dass sich gemäß der Erfindung neben einer vorteilhaften Erhöhung der maximalen Hubkraft, insbesondere zur Optimierung der Energieeffizienz von Hubbewegungen über den gesamten Nutzlastbereich einer Maschine verwirklicht werden kann.

The main differences between the present invention and the prior art are as follows:

• - By the check valve arrangement 6.3 as well as the differential pressure control valve 6.4 an advantageous bias of the tilt cylinder circuit is achieved. Because of this bias, the load-holding valve 3.3 held in its open switch position. This ensures that the load pressure is transmitted from the piston side K of the tilt cylinder 3.1 not through the load-holding valve before the start of the lifting movement 3.3 prevented.
• - To the differential pressure control valve 6.1 to open, there is no advance movement of the compensation cylinder beforehand 4.1 and therefore no energy exchange from the stroke section to the piston side K of the compensation cylinder 4.1 necessary. The differential pressure control valve 6.1 is based on an additional pressure signal or that of the second control line IV to connection X1 of the valve block 6th steered up.
• - The stroke-supporting force effect of the compensation cylinder 4.1 , using the one on the piston side K of the tilt cylinder 3.1 acting load pressure, is available in an advantageous manner due to the two features described above, even before a lifting movement of the lifting arm 1.1 takes place.
• - The lifting-supporting function is activated from a load pressure on the piston side K of the lifting cylinder 2.1 effective, which is high enough in an advantageous manner, the differential pressure control valve 6.1 to steer up. Depending on the control ratio of the differential pressure control valve 6.1 this pressure is low enough that the lift-supporting function of the circuit is effective over the entire payload range of the machine.
• - It follows that, according to the invention, in addition to an advantageous increase in the maximum lifting force, in particular to optimize the energy efficiency of lifting movements over the entire payload range of a machine.

The circuit variants shown by way of example are basically also without the additional differential pressure control valve 6.4 functioning. However, this valve is essential for reliable operation in every load situation 6.4 given.

In addition to the variant according to the invention according to 1 , ie with the override differential pressure control valve 6.1 , the additional pressure signal via 6 / X1 of the valve block 6th receives, alternatively also a separate control according to a second variant according to the invention as in 2 to realize shown. Here, for example, a parallel to the valve 6.1 connected further valve 6.5 , in particular a directional control valve 6.5 , are provided. This valve can, for example, by an (electromagnetic) magnetic force 6.5 be electronically controlled. Here, electronic signals, for example from an advantageous sensor, can control the valve 6.5 control / operate. Preferably the valve 6.5 due to the lifting movement on the directional control valve 2.2 actuated / controlled, eg a magnet on the valve is activated by means of the above-mentioned sensor signal 6.5 activated / switched on or switched off so that the valve 6.5 opens / closes. The differential pressure control function can either be activated directly by operating the valve 6.5 be overridden by themselves or by the parallel to the differential pressure control valve 6.1 switched valve 6.5 or 2/2-way valve 6.2 can be bypassed (cf. 2 ).

The two embodiments essentially have in common the principle, the pressure-reducing functions of the valves in the course of the line between the connections 3.1 / K of the tilt cylinder 3.1 and 4.1 / K of the compensation cylinder 4.1 to be overridden in a controlled manner without impairing the safety-relevant functions of the valves. Thus, overriding the differential pressure control valve can be advantageous features of the invention 6.1 by an additional signal at the moment of an active lifting movement of the loading system and the holding of the load holding valve 3.3 are designated in its open switching position by biasing the tilt cylinder circuit.

By canceling the pressure-reducing effect, there is an additional force component on the compensation cylinder that can be used to lift the load 4.1 to disposal. This increases the maximum possible lifting force of the telehandler 1 . In addition, regardless of the size of the load placed by the lifting cylinder 2.1 The force to be overcome and thus the required working pressure for the lifting process is reduced. Compared to the state of the art, this leads to a general increase in energy efficiency during lifting processes.

Compared to previous hydraulic systems, the system according to the invention requires less energy to lift the same load. That means less work has to be done around the lift arm 1.1 to raise. This is due to the fact that the required pressure in the lifting cylinder 2.1 to raise a defined load is lower than with previous systems. One reason for this is that, according to the invention, the load pressure of the tilt cylinder 3.1 to the full extent when lifting on the bottom side of the compensating or compensating cylinder 4.1 is available and thus the lifting cylinder 2.1 supported.

Claims (11)

Power machine (1), in particular a motor vehicle (1), with a frame (1.6) and a boom (1.1) which can be pivoted about a first pivot axis (1.8) in relation to the frame (1.6), a pivoting stroke cylinder (2.1) for pivoting, in particular Raising and lowering, the boom (1.1) is provided opposite the frame (1.6), the boom (1.1) having a load-bearing device (1.3) for picking up / fixing a load-bearing device (1.4) such as a (exchangeable) tool or the like, in particular a load fork , a gripping arm, a shovel or (people) stage, wherein a tilting lifting cylinder (3.1) is provided for tilting / pivoting the load-bearing device (1.3) with respect to the boom (1.1), so that the load-bearing device (1.3) about a second pivot axis (1.9) is adjustable / pivotable in relation to the boom (1.1), a compensation stroke cylinder (4.1) being arranged between the boom (1.1) and the frame (1.6) so that the compensation stroke cylinder (4.1) and / or a piston of the compensation stroke cylinder (4.1) is adjustable in relation to a cylinder of the compensation stroke cylinder (4.1) when the boom (1.1) is pivoted about the first pivot axis (1.8), with at least one hydraulic unit comprising a hydraulic oil / fluid for actuation and / or pressurization of the lifting cylinders (2.1, 3.1, 4.1) is provided, with at least one tilting actuation unit (3.2), in particular a tilting valve (3.2), being provided for actuating and / or pressurizing the tilting lifting cylinder (3.1), with at least one pivoting actuation unit (2.2 ), in particular a swivel valve (2.2), is provided for actuating and / or pressurizing the swivel stroke cylinder (2.1), a first connecting line (I) and a second connecting line (II) being provided between the tilting stroke cylinder (3.1) and the compensation stroke cylinder (4.1) is, the first connecting line (I) at least one first, controllable actuator (6, 6.1), at least one first control line (III) for controlling / actuating the first, controllable actuator (6, 6.1) provided between the first actuator (6, 6.1) and the second connecting line (II) is, characterized in that at least one second control line (IV) is provided for controlling / actuating the first actuator (6, 6.1) and / or that at least the first connecting line (I) comprises at least one second, controllable actuator (6.5). Engine after Claim 1 , characterized in that the second control line (IV) is arranged between the swivel actuation unit (2.2) and the first actuator (6, 6.1). Engine according to one of the preceding claims, characterized in that the second, controllable actuator (6.5) is arranged hydraulically parallel to the first, controllable actuator (6.1), wherein the first, controllable actuator (6.1) and the second, controllable actuator (6.5) are arranged between a first branch point (31) and a second branch point (32) of the first connecting line (I). Engine according to one of the preceding claims, characterized in that the first controllable actuator (6, 6.1) is designed as a first differential pressure control unit (6.1) and / or first differential pressure control valve (6.1). Engine according to one of the preceding claims, characterized in that the first controllable actuator (6, 6.1) is designed as a pressure limiting unit (6.1) and / or first pressure limiting valve (6.1) and / or pressure reducing valve (6.1). Engine according to one of the preceding claims, characterized in that the first connecting line (I) comprises at least one first load-holding unit (6, 6.1) and / or a first load-holding valve (6.1). Engine according to one of the preceding claims, characterized in that at least one third control line (III) is provided between the second connecting line (II) and the first load holding unit (6.1) and / or the first load holding valve (6.1). Engine according to one of the preceding claims, characterized in that between the tilt actuation unit (3.2) and the tilt stroke cylinder (3.1) and / or the compensation stroke cylinder (4.1) and / or the first, controllable actuator (6.1) and / or the second, controllable actuator (6.5) at least one second load-holding unit (6.3) and / or a second load-holding valve (6.3) is arranged. Engine according to one of the preceding claims, characterized in that the second load holding unit (6.3) is designed as a check valve arrangement (6.3) and / or comprises at least two second load holding valves. Engine according to one of the preceding claims, characterized in that the second connecting line comprises at least one second differential pressure control unit and / or a second differential pressure control valve. Engine according to one of the preceding claims, characterized in that at least one third load holding unit (2.3) and / or a third load holding valve (2.3) is arranged between the swivel actuation unit (2.2) and the swivel stroke cylinder (2.1).

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