HYDRAULIC MACHINE WITH A BOOM THAT CAN BE SWIVELED AROUND A SWIVEL AXIS

Description

[0001] The invention relates to a hydraulic machine, in particular a motor vehicle such as an excavator, wheel loader, tractor, telescopic loader or the like, with a boom pivotable about a pivot axis with respect to a frame according to the preamble of claim 1. State of the art

[0002] For example, vehicles such as excavators, wheel loaders, telehandlers, snow groomers, tractors, combine harvesters, forage harvesters, forestry / hauling cranes, so-called "harvesters," front loaders, etc. have been in use for years, for example, in civil engineering and construction, recycling and waste management, gardening and landscaping, as well as in forestry and agriculture. Various loads or tools can be attached to a boom or swivel arm. In addition to standard attachments or tools such as buckets and forks, other tools such as load hooks, concrete buckets, sweepers, work platforms, cable winches, dozer blades, and grapples can also be used. Quick-change plates are available for rapid tool changes.

[0003] For example, telehandler loading systems feature a lifting arm with at least one extension stage, which is usually pivotally mounted at the rear of the vehicle. Raising and lowering the boom or lifting arm is accomplished by a hydraulic lifting cylinder, which is controlled or operated by the driver via a directional control valve. In addition to the directional control valve, a lowering brake valve is used for controlled lowering of the load.

[0004] With the help of a corresponding hydraulic control unit or the controllable directional control valve, it is usually possible to switch between a lowering mode for lowering the boom and a lifting mode for raising the boom as well as a so-called "neutral position" or a holding mode for holding the boom.

[0005] To initiate the lowering movement, the control valve and the lowering brake valve are typically controlled with the same pilot pressure. This directs an oil flow from a hydraulic pump via the control valve to the rod side of the lifting cylinder. At the same time, the lowering brake valve opens and directs the oil displaced from the piston side to the tank via the control valve. This sets the lifting cylinder in motion, and the load is lowered. Due to the shared control, the characteristics of the control valve and the lowering brake valve must be precisely coordinated.

[0006] The lowering brake valve is currently actuated via a hydraulic pilot signal. The pilot pressure required for actuation is provided by a pressure reducing valve, which provides a pressure proportional to the control current. Due to its geometric design, the lowering brake valve is load-compensated, meaning that the valve maintains approximately the same volume flow regardless of the payload.

[0007] To increase efficiency when lowering the loading system, a so-called "regeneration" can be integrated, e.g., EP 1 915 538 B1. For this purpose, the piston and rod sides of the lifting cylinder are additionally connected when lowering the load. Due to the unequal effective areas, a portion of the oil flow is directed from the piston to the rod side. The excess oil flows to the tank via the control valve. This reduces the oil flow supplied to the pump and saves energy to a certain extent.

[0008] Furthermore, US 2018 / 0112686 A1 discloses a hydraulic circuit for the aforementioned motor vehicles, in which the return flow is routed directly into the tank, bypassing the control valve. This direct connection reduces pressure losses in the return flow. In contrast to the previously described solution, a load-holding valve is used instead of a lowering brake valve. In this case, the pressure of the supplied oil flow is used to control the valve, rather than an external pilot pressure.

[0009] In addition, non-mobile hydraulic machines with a hydraulically pivoting boom or a vertically adjustable mechanism are also known, wherein a pivoting mechanism is provided to vertically adjust a load or a tool, e.g. presses, punches, bending machines or the like.

[0010] A disadvantage of existing hydraulic machines, however, is that the control valve must provide a slightly larger oil flow than the counterbalance valve releases under load. Due to the shared piloting, precise coordination of the control valve and counterbalance valve is not possible at every operating point. This results in back pressures upstream of the counterbalance valve (piston side), which must be overcome with energy-intensive drive power.

[0011] In addition, the following disadvantages can arise when several consumers are operated in parallel using a shared pump: A) To lower the loading system, the rod side of the lifting cylinder must be supplied with oil. This reduces the usable pump flow rate for supplying additional consumers.

[0012] B) When several consumers with different pressure levels are operated in parallel, additional throttling losses occur due to the oil flow and pressure of the pump required for lowering.

[0013] In addition, a hydraulic machine with a lowering sensor is known from US 2015 / 059568 A1 and a hydraulic circuit with a lowering sensor is known from US 2005 / 051024 A1. Object and advantages of the invention

[0014] The object of the invention is therefore to propose a hydraulic machine, in particular a motor vehicle, which, compared to the prior art, realizes an improved or more efficient mode of operation, in particular an improved pressurization or energy utilization of the hydraulic system.

[0015] This object is achieved by the features of claim 1, starting from a hydraulic machine, in particular a motor vehicle, of the type mentioned in the introduction. Advantageous embodiments and further developments of the invention are possible through the measures mentioned in the subclaims.

[0016] Accordingly, a hydraulic machine according to the invention, in particular a motor vehicle, is characterized in that at least one lowering sensor generating a lowering signal is provided for detecting an actual lowering parameter of the lowering operation, that an actual-target comparison unit generating at least one lowering control signal is provided for comparing the actual lowering parameter with a target and / or limit parameter, wherein, in the event that the actual lowering parameter corresponds to the target and / or limit parameter, the lowering control signal is provided / configured for actuating the control unit and / or the pressure generating device and / or for switching the controllable lifting cylinder control element, so that pressurization of the hydraulic oil / fluid of the piston rod chamber is provided, and that in the lowering operation of the boom, at least one regeneration connection line is provided / configured between the piston chamber and the piston rod chamber,so that hydraulic oil / fluid can flow from the piston chamber to the piston rod chamber, wherein the regeneration connection line comprises at least one lowering brake element.

[0017] This measure(s) will make the hydraulic system significantly more flexible during the lowering process. This allows for, among other things, a particularly energy-efficient and / or automated and / or more "smooth" or even / continuous lowering operation.

[0018] Previously, lowering operation was carried out according to the switching positions of the actuators or control valves, or the like, set / actuated by the driver. The hydraulic system could not and did not intervene automatically in the lowering operation. According to the invention, the advantageous lowering sensor can now detect a favorable actual lowering parameter during lowering operation and use it for improved lowering operation. This enables previously unattainable improvements to the hydraulic system, especially for energy-saving and / or more continuous lowering of the boom.

[0019] For example, in the event of an unusual and / or unforeseeable operating situation / incident and / or changing conditions, the sensor can detect this actual state or the corresponding actual lowering parameter and use it to advantageously adapt and / or modify the lowering process or operation. This opens up completely new (more automated) operating possibilities with significantly improved comfort and / or energy consumption. For example, the pressure generation unit can be operated less frequently or for a shorter period of time, which can reduce energy consumption.

[0020] In addition, part of the oil is not fed into the tank, but is fed directly back to the piston rod side.

[0021] For example, a lowering sensor according to the invention is conceivable, which is designed as a speed sensor for detecting a lowering speed, e.g. for detecting the adjustment speed or the retraction of the lifting cylinder, ie the piston, or the angular speed at the pivot axis of the boom.

[0022] The lowering sensor could also be designed, for example, as a contact sensor for detecting contact with the boom and / or the load-carrying device or tool. For example, it is conceivable that contact with the ground, contact during loading on a vehicle trailer, or similar events could be detected. A distance sensor, an optical sensor, a capacitive or inductive sensor, a radar sensor, or the like could be used, whereby the distance and / or contact and / or a reduction / change in the lowering process could be detected.

[0023] In principle, during such processes, i.e. where the boom and / or the tool or the load touches something, which can occur frequently during construction work or the like, in particular often unforeseeable events such as landslides from piles of gravel or sand, etc., falling objects during demolition work, etc., and / or in cases where the weight or the force of the boom (with or without additional load) is no longer (fully) sufficient for lowering, e.g. due to internal hydraulic losses and / or frictional resistance etc. of the hydraulic system or the mechanical components moving / adjusting in the process, the operating conditions during lowering can change considerably, so that the operation of the hydraulic system or lifting cylinder and / or the pump system or the pressure generation unit can advantageously be adjusted by means of the advantageous target / actual comparison or the lowering control signal orThe lowering parameter can be adjusted / changed according to the invention. This advantageously eliminates the need for active intervention by the driver in the hydraulic system and / or control system, which would otherwise result in so-called "dead times" or adverse reaction times. Therefore, according to the invention, lowering operation can be implemented much faster, more evenly, and / or more energy-efficiently, while also avoiding human error.

[0024] Preferably, the lowering sensor is designed as a pressure sensor for detecting the pressure of the hydraulic oil / fluid, in particular the so-called "load pressure." This allows a change or undershoot / overshoot of the hydraulic pressure in the hydraulic system or the hydraulic fluid or the hydraulic oil to be advantageously detected and used according to the invention, particularly for the advantageous target-actual comparison. This measure enables a particularly cost-effective implementation, since a wide variety of pressure sensors for hydraulic systems are already commercially available and therefore inexpensive. Furthermore, even very small pressure differences / changes can be detected and advantageously used according to the invention.

[0025] A particular advantage of the invention in the advantageous detection of the load pressure is that a load pressure is built up on the piston side of the lifting cylinder due to a picked-up load and / or the dead weight of the loading system or the (entire) boom, whereby the load pressure is present even without a tool / attachment, primarily due to the dead weight of the boom or the loading system. This is also referred to as the holding pressure of the empty loading system. When a load is picked up, this pressure is higher or continues to increase as long as the loading system is not in contact with the ground or another obstacle. If the boom or the loading system comes into contact with an obstacle, the boom or the loading system is supported by it and thus relieved. If the holding pressure is used / specified as a limit / target / reference value for advantageous control or switching according to the invention, e.g.For a transition from passive to active lowering, switching to active lowering occurs whenever the boom or loading system is supported from below by an obstacle and thus relieved of load. The load pressure, or "actual pressure," then drops to a value that is lower than the holding pressure, or "target pressure."

[0026] With very light booms or loading systems, or with small valves and line cross-sections, etc., the resulting lowering speed without a load may be too low. This can be advantageously counteracted, for example, by selecting a reference value higher than the holding pressure of the empty loading system. In this case, active lowering is advantageously performed when the driving weight of the load and loading system is too low. Heavy loads, on the other hand, continue to be lowered passively, saving energy.

[0027] In an advantageous variant of the invention, the pressure sensor is arranged in the regeneration connection line and between the piston chamber and the lowering brake element, or in / on the piston chamber. This advantageously allows the pressure of the piston chamber or corresponding lines / sections hydraulically connected to it to be measured and used advantageously, particularly in the event of changes in the actual pressure, according to the invention. This allows even the smallest actual parameter changes to be recorded very precisely, while also allowing the invention to be implemented in a very compact and space-saving manner.

[0028] For example, the pressure in the piston chamber and / or at least in an adjacent section of the regeneration connection line drops upon contact of the boom and / or tool or load suspension on the ground, on an object such as a vehicle trailer, dump truck or the like, which can be detected according to the invention and used for advantageous control.

[0029] In a particular development of the invention, the lowering sensor is designed as a load sensor for detecting a load / stress on the boom and / or the load-carrying device and / or the frame. Here, too, contact or contact of the boom and / or the load-carrying device or the tool can be used to change the actual parameters according to the invention.

[0030] The lowering / load sensor is preferably designed as a frame sensor for detecting a frame load / strain. For example, the frame sensor is designed as an axle load sensor for detecting an axle load / strain of a vehicle axle, in particular a rear axle, in particular as a strain gauge (SG) for detecting a bending / length change of the vehicle axle. When the boom is lowered (with or without additional load), a bending moment or load is generated on the frame or on one of the (two) drive axles / axles, in particular on the rear axle in telehandlers. This bending moment or load changes significantly upon contact or resting of the boom or the tool and / or the load and can thus be used according to the invention for the advantageous actual-target comparison.

[0031] This is a particularly advantageous embodiment of the invention, since many construction vehicles, telehandlers, or the like already have a load or axle load for detecting a dangerous situation such as the tipping of the vehicle or telehandler, and these can be advantageously used for the invention. Consequently, both the design and financial outlay can be kept very low.

[0032] Thus, the existing sensor can be evaluated or used for other purposes, such as detecting a dangerous tipping situation, etc., for the advantageous actual parameter comparison according to the invention without significant effort for retrofitting and / or by means of software programming. This further reduces the costs of the invention.

[0033] In the embodiment of the invention in which the sensory detection of the actual lowering parameter is realized via the load on the rear axle, the invention takes advantage of the fact that the weight of the picked up load advantageously generates a moment about the contact area of ​​a first wheel / drive axle, in particular the front axle in the case of telehandlers, which moment usually acts in a forward tipping direction in the case of telehandlers, for example. As a result, the other or second wheel / drive axle or, for example, the rear axle in the case of telehandlers, is relieved more the heavier the picked up load. The weight of the machine at its center of gravity counteracts this tipping moment. If the boom or loading system is supported by an obstacle, the tipping moment about the first axle, or in the case of telehandlers, the front axle, is reduced, and the load acting on the second axle or, in the case of telehandlers, the rear axle, increases.

[0034] Thus, according to the invention, the load on the second axle or, for example, in the case of telescopic loaders, on the rear axle, which is measured, for example, by means of strain gauges or so-called "strain gauge measurement" or the like, can also be used to detect whether the boom or the loading system is in contact with an obstacle or whether the load taken up is too small to cause a sufficiently rapid lowering movement.

[0035] Advantageously, a control device is provided for controlling the lowering brake element, wherein the control device is designed at least partially separately from the control unit of the controllable lifting cylinder control element, so that the lowering brake element can be controlled separately from the lifting cylinder control element. This allows the control device and the control unit or the controllable lifting cylinder control element to be operated (largely) independently of one another. This opens up completely new possibilities for controlling the hydraulic system or the lifting cylinder and / or the controllable lifting cylinder control element, etc.

[0036] Preferably, at least one relief element / valve is provided, with at least one branching unit arranged between the lowering brake element and the lifting cylinder control element, and with the relief element / valve arranged between the branching unit and a hydraulic accumulator / tank, so that during lowering operation, excess hydraulic oil / fluid from the piston chamber can be fed to the hydraulic accumulator / tank. This advantageously compensates for differences in the oil / fluid quantities involved or feeds them to the tank / accumulator.

[0037] In general, the principle according to the invention can be used, depending on given measured variables or recorded actual lowering parameters (usually the load pressure on the lifting cylinder), whereby it is advantageously possible to automatically switch between load-induced lowering movement and active lowering of loads. This can be advantageously applied to hydraulic machines in which loads are lifted with the aid of hydraulic cylinders, but lowering them is not possible without restrictions due to their own weight, or where forces must be actively applied in the lowering direction at times. In this case, the boom or loading system is advantageously lowered in a controlled manner using gravity, which leads to a saving in pumping energy and / or an improvement in comfort and / or a more continuous lowering movement. Example

[0038] An embodiment of the invention is shown in the drawing and is explained in more detail below with reference to the figures.

[0039] In detail: Figure 1 shows a schematic representation of a telehandler with a hydraulic swivel cylinder, Figure 2 shows a first schematic hydraulic circuit diagram for the swivel cylinder of the telehandler, Figure 3 shows a second schematic hydraulic circuit diagram for the swivel cylinder of the telehandler, and Figure 4 shows a third schematic hydraulic circuit diagram for the swivel cylinder of the telehandler.

[0040] In the Figures 2 to 4 are various schematic hydraulic systems according to the invention of a mobile hydraulic machine or a motor vehicle such as a telescopic loader 1 according to Figure 1outlined. The telehandler 1 comprises, among other things, a boom 1.1 or a telescopic lifting arm 1.1, which is adjustable / pivotable relative to a vehicle frame 1.6 about a first pivot axis 1.8 by means of a pivot cylinder 2.1 or lifting cylinder 2.1 having a piston 22 and a piston rod 23. This allows the height of the boom arm 1.1 to be adjusted. The length adjustment can be implemented in a known manner in one or more stages and is not illustrated or explained in detail here.

[0041] The telehandler 1 also has, in a known manner, a driver's cab 1.7, in which one or two or more control elements for driving and for operating the hydraulic system are advantageously provided. Furthermore, wheels 5 or drive chains (not shown), e.g., of an excavator or the like, are provided in a known manner, which are preferably driven by a drive motor, e.g., a diesel engine and / or electric motor and / or hydraulic motor, and / or steerable by the driver.

[0042] A load-bearing device 1.3 or tool carrier 1.3 is mounted on the boom 1.1 or telescopic boom arm 1.1 and can pivot about a second pivot axis 1.9. A load 1.4 or a tool 1.4 is arranged at an arm end 1.5, whereby the tool carrier 1.3 can be adjusted / pivoted relative to the arm end 1.5 using a tilting cylinder 3.1 or tilt cylinder 3.1.

[0043] As is already commercially available, the tilt cylinder 3.1 can advantageously be hydraulically connected to a compensation cylinder 4.1 via a first connecting line and a second connecting line (not shown in detail), i.e., hydraulic fluid / oil can be exchanged via the two connecting lines or they are integrated into a common hydraulic circuit. As is known, this ensures that the load 1.4 or the tool 1.4 remains in a predetermined position or orientation, e.g., in a horizontal position, when the boom 1.1 is pivoted, which is usually a great advantage in practice.

[0044] In Figure 2 a first schematic hydraulic circuit diagram for the swivel cylinder 2.1 of the telescopic loader 1 with a lowering sensor 6 designed as a pressure sensor 6 according to the invention is shown.

[0045] During lowering operation, the lowering movement of the boom 1.1 is initially controlled solely by a lowering brake valve 13. For this purpose, a regeneration valve 14 and a relief valve 15.1 or, alternatively, a lift arm damper 15.2 are opened. Piloting the lowering brake valve 13 opens it, and the oil Q2 displaced from one piston side or a piston chamber 20 is directed through the regeneration valve 14 to the rod side or a piston rod chamber 21.

[0046] Due to the unequal effective areas or volumes of the piston side 20 and the rod side / chamber 21, only a partial oil quantity Q1 can be supplied to the rod side or the piston rod chamber 21. An excess oil flow Q3 = Q2 - Q1 is optionally discharged from a branching point 30 via the relief valve 15.1 or 15.2 to tank T to enable a lowering movement of the boom 1.1. By bypassing a control valve 12, no engine power or pump power of a pump P is required to lower the loading system or the boom 1.1. Only the weight of the boom 1.1 is used as the driving force for the lowering operation, i.e., a "passive" lowering operation takes place.

[0047] Only when the weight force and thus the load pressure are no longer sufficient to lower the loading system, the control valve 12 is activated additionally or "parallel" to the lowering brake valve 13 and the regeneration valve 14 and relief valve 15.1, 15.2 are closed.

[0048] The switching occurs (automatically) based on the load pressure or actual pressure of the oil quantity Q2 or the oil flow Q2, which is detected according to the invention by the pressure sensor 6. This is advantageously done in such a way that the pressure sensor 6 sends / transmits a sensor signal 8 to a controller 7, and that this controller 7, by means of a comparison unit 9, compares the transmitted actual / sensor signal 8 or actual parameter within the meaning of the invention with a stored / stored target parameter / value, wherein, if necessary, a microprocessor unit or a microcontroller 11 or the like is advantageously used.

[0049] In the event that the actual parameter corresponds to the target parameter / value during lowering operation, or if these are equal, the controller 7 or the comparison unit 9 advantageously sends a lowering control signal 16 to the pump P and / or a control signal 17 to the control valve 12, so that the latter switches to the lowering position and so that, if necessary, the pump P maintains the operating pressure or pumps oil Q1 to the rod side or into the piston rod chamber 21. Consequently, an "active" lowering operation is realized, for which energy or pumping power is required.

[0050] This can also be the case when changing from pulling to pushing loads, as happens, for example, when the tool 1.4 is placed on the ground or on an obstacle not shown.

[0051] At the operating point at which the control 7 switches from "passive" to "active" lowering operation, the "energy-free" or gravity / weight-driven lowering operation, which could also be referred to as "gravity lowering" function, is no longer active and the system behaves almost like previously commercially available and pump energy-consuming hydraulic systems or lowering modes.

[0052] Due to the advantageous separate control of the valves 12 and 13, i.e. control signal 17 and a separate or second control signal 18, and thus independent parameterizable characteristics in a software, even in the previously known or so-called conventional lowering operation, throttling losses and thus energy consumption can be additionally reduced in an advantageous manner.

[0053] In a further advantageous variant of the invention, a characteristic curve stored in software (valve current flow as a function of the required lowering speed) for the lowering brake valve 13 can be replaced by a characteristic map (valve current flow as a function of the required lowering speed and the measured load pressure). This allows the volume flow control behavior of the lowering brake to be further optimized.

[0054] In principle, according to the invention, an advantageous retrofitting of previously conventional hydraulic systems can be realized in an advantageous manner without major structural and / or economic as well as control-technical expenditure.

[0055] The relief valve 15.1 can be installed as in Figure 2Alternatively, it can also be installed on the piston side of the lifting cylinder 2.1, i.e., as a relief valve 15.2. This advantageously reduces the volume flow through the regeneration valve 14 and minimizes associated throttling losses, which negatively impact the lowering speed. However, in this case, the valve 15.2 can no longer be used to relieve the rod side when the lifting arm damping is activated.

[0056] The described so-called "gravity-lowering" function can be used as in Figure 3 shown can be realized with a switchable lowering brake valve 13 or a lowering brake unit, which comprises various check valves and / or load holding valves (cf. Figure 3 ). This allows the individual, separate and switchable regeneration valve 14 to be accessed according to Figure 2can be omitted. In this circuit, the relief valve 15.1 can also be arranged alternatively on the piston crown side (not shown in detail).

[0057] In addition, the described so-called "gravity lowering" function can also be used as in Figure 4 shown can be realized with another, switchable lowering brake valve 13 or another lowering brake unit, which in turn comprises various check valves and / or load holding valves (cf. Figure 4 ). Here too, the individual, separate and switchable regeneration valve 14 can be used according to Figure 2 Compared to Figure 3 The relief valve 15.2 is shown in the alternative position. In this circuit, the relief valve 15.2 can also optionally be arranged on the piston crown side (not shown in detail).

[0058] In the Figures 3 and 4A further illustration of the control 7 including its advantageous components / parts as well as its signal lines 16, 17, 18 etc. has been omitted for reasons of clarity. The corresponding controls 7 for the circuits according to the Figures 3 or 4 However, they can be compared to Figure 2 be trained.

[0059] The discharge of the excess volume flow Q3 during lowering is also generally possible via control valve 12. For this purpose, control valve 12 should / must be designed with an alternative switching position that relieves the working connections to tank T and keeps the supply connection closed. This can be achieved via the so-called neutral position of the valve spool or an additional switching position, which is well known to those skilled in the art.

[0060] A further advantageous optimization of the operating behavior is possible, for example, by measuring / detecting the pressure difference at the lowering brake valve 13. For this purpose, an additional pressure measuring point is advantageously provided or implemented, e.g., with a second pressure sensor and / or a pressure difference sensor. The characteristic map then advantageously yields the actual parameter or current value advantageous for controlling the valve, for example, depending on the required or specified lowering speed and the pressure difference present at the lowering brake valve 13.

[0061] The switching according to the invention between so-called "gravity lowering" and conventional or "active" lowering is also possible on the basis of the load signal of the overload system on the rear axle of the telescopic loader 1, ie on the wheel axle of the right in Figure 1drawn wheels 5. In this case, the pressure sensor 6 can be dispensed with, since the corresponding axle sensor is designed as a lowering sensor according to the invention.

[0062] In addition, interference on the system can be compensated for by an optional or advantageous measurement of a geometric parameter, such as the lifting angle of the lifting arm or boom 1.1 and / or the stroke of the lifting cylinder 2.1 and / or feedback of the signal to a controller (control loop) of the control system 7.

[0063] In the outlined embodiments, the lowering brake valve 13 can optionally be actuated via a first, hydraulic pilot signal or via the control line 18 and / or the control valve 12 can optionally be actuated via a (separate) second, hydraulic pilot signal or via the control line 17. Thus, direct electromagnetic actuation of the valves 12 and / or 13, e.g., by means of electrical control lines 17, 18, is also possible, as is electrical control of the pump P by means of electrical control line 16. It is of great advantage if the lowering brake valve 13 and the directional control valve 12 or control valve 12 can be controlled independently of one another.

[0064] The invention leads to particular advantages or effects if, for example, with sufficient weight force (load pressure), the loading system or the boom 1.1 can be lowered in a controlled manner without the assistance of the motor or the pump P, thereby saving energy.

[0065] By bypassing control valve 12 also eliminates the need for oil flow and pressure from pump P to lower the loading system or boom 1.1. This allows for the advantageous parallel operation of multiple hydraulic consumers in the hydraulic system, resulting in a higher usable pump flow rate for the other hydraulic consumers / components. Furthermore, throttling losses are avoided when operating multiple consumers at different pressure levels.

[0066] The advantageous variants of the invention can be retrofitted very easily and thus offered as options for the customer, which advantageously increases the flexibility and comfort for the customer.

[0067] In addition, the invention can be optimized / modified without great design and economic effort and flexibly, especially via advantageous software parameters, and thus adapted to different operating conditions and machines or vehicles and / or applications / areas.

[0068] Thus, the advantageous embodiments of the invention include, among others, the following optional features: (If possible) separate piloting of control valve 12 and lowering brake valve 13, (possible) connection of piston and rod side during lowering, i.e. so-called "regeneration" or oil flow from the piston 20 to the piston rod chamber 21, (if possible) direct discharge of the excess volume flow Q3 to the tank T through (already present / existing) relief valve 15.1, 15.2 of the so-called "lift arm damping" and advantageous switching off / switching of the so-called "gravity lowering" function on the basis of the recorded actual parameter such as the measured load pressure of the oil quantity Q2 of the piston side or the piston chamber 20 according to the invention.

Claims

1. Hydraulic machine (1), in particular motor vehicle (1) such as an excavator, wheel loader, tractor, telescopic loader (1) or the like, having a boom (1.1) pivotable about a pivot axis (1.8) with respect to a frame (1.6), wherein the boom (1.1) comprises a load receiving device (1.3) for receiving / fixing a load receptacle (1.4) such as a tool (1.4) or the like, in particular a loading fork (1.4), a gripper arm, a bucket or platform, wherein a lifting cylinder (2.1) having a piston (22) and a piston rod (23) is provided for pivoting, in particular raising and lowering, the boom (1.1) with respect to the frame (1.6), wherein the lifting cylinder (2.1) is designed as a double-acting cylinder (2.1) with a piston chamber (20) and a piston rod chamber (21), wherein a hydraulic unit comprising at least one pressure generating device (P), in particular hydraulic pump (P), for pressurizing a hydraulic oil / liquid is provided for actuating and / or pressurizing the lifting cylinder (2.1), in particular the piston chamber (20) and / or the piston rod chamber (21), wherein at least one lifting cylinder control element (12) controllable by means of a control unit (7), in particular a directional control valve (12), is provided for controlling the lifting cylinder (2.1) and / or for switching over between a lowering operation for lowering the boom (1.1) and / or a lifting operation for raising the boom (1.1) and / or a holding operation for holding the boom (1.1), characterized in that at least one lowering sensor (6) generating a lowering signal (8) is provided for detecting an actual lowering parameter of the lowering operation, in that an actual / target comparison unit (9) generating at least one lowering control signal (16, 17, 18) is provided for comparing the actual lowering parameter with a target and / or limit parameter, wherein, in the case of the actual lowering parameter corresponding to the target and / or limit parameter, the lowering control signal is provided for actuating the control unit (7) and / or the pressure generating device (P) and / or for switching over the controllable lifting cylinder control element (12), so that at least one pressurization of the hydraulic oil / liquid of the piston rod chamber (21) is provided, and in that, during the lowering operation of the boom (1.1), at least one regeneration connecting line (19) is provided / formed between the piston chamber (20) and the piston rod chamber (21), so that hydraulic oil / liquid can flow from the piston chamber (20) to the piston rod chamber (21), wherein the regeneration connecting line (19) comprises at least one lowering brake element (13).

2. Hydraulic machine according to Claim 1, characterized in that the lowering sensor (6) is designed as a pressure sensor (6) for detecting a pressure of the hydraulic oil / liquid.

3. Hydraulic machine according to Claim 2, characterized in that the pressure sensor (6) is arranged in the regeneration connecting line (19) and between the piston chamber (20) and the lowering brake element (13) or in / on the piston chamber (20).

4. Hydraulic machine according to any of the preceding claims, characterized in that the lowering sensor (6) is designed as a load sensor for detecting a load / loading of the boom (1.1) and / or of the load receptacle (1.4) and / or of the frame (1.6).

5. Hydraulic machine according to any of the preceding claims, characterized in that the lowering / load sensor (6) is designed as a frame sensor for detecting a frame load / loading.

6. Hydraulic machine according to Claim 5, characterized in that the frame sensor is designed as an axle load sensor for detecting an axle load / loading of a vehicle axle, in particular a rear axle.

7. Hydraulic machine according to Claim 6, characterized in that the axle load sensor is designed as a strain gauge (DMS) for detecting a bending / change in length of the vehicle axle.

8. Hydraulic machine according to any of the preceding claims, characterized in that a control device (7) is provided for controlling the lowering brake element (13), wherein the control device is designed at least partially separately from the control unit (7) of the controllable lifting cylinder control element (12), so that the lowering brake element (13) can be controlled separately from the lifting cylinder control element (12).

9. Hydraulic machine according to any of the preceding claims, characterized in that at least one relief element / valve (15.1, 15.2) is provided, wherein at least one branching unit (30) is arranged between the lowering brake element (13) and the lifting cylinder control element (12) and wherein the relief element / valve (15.1, 15.2) is arranged between the branching unit (30) and a hydraulic accumulator / tank (T), so that, during lowering operation, excess hydraulic oil / liquid (Q3) of the piston chamber (20) can be supplied to the hydraulic accumulator / tank (T).

10. Motor vehicle (1) such as an excavator, wheel loader, tractor, telescopic loader (1) or the like, having a hydraulic machine according to any of the preceding claims.