Drive train assembly for driving a working unit with a fluctuating load

Abstract

The present invention relates in general to working machines with working units which are subject to fluctuating loads or have a fluctuating power consumption. The invention relates to a drive train assembly for driving such a working unit having fluctuating power consumption from a working source, having a unit transmission which converts a drive movement of the drive source into a working movement of the working unit, and which is connected to the working unit on one side by way of a transmission output element and on the other side to the drive source by way of a transmission input element, and having a flywheel energy store for mitigating load surges or fluctuations. The invention also relates to the working machine having a drive unit with fluctuating power consumption and said drive train assembly having a flywheel energy store. According to the invention, the flywheel energy store is to be connected to the drive train section leading from the unit transmission to the working unit to be driven via a branching flywheel mass section at different engagement points such that the flywheel mass moments are split and the loads are distributed to different engagement points such that overloading and premature wear at a single engagement point can be avoided and the overall size can also be reduced substantially as a result of the load distribution.

Description

[0001] 3182-25 T / wb

[0002] Liebherr-Components Biberach GmbH

[0003] Drivetrain assembly for powering a work unit with a fluctuating load

[0004] The present invention relates generally to working machines with working units that are subject to fluctuating loads or have fluctuating power consumption. The invention relates, on the one hand, to a drive train assembly for driving such a working unit with fluctuating power consumption from a power source, comprising a drive unit transmission that converts a drive movement of the power source into a working movement of the working unit and is connected on one side to the working unit via a transmission output element and on the other side to the power source via a transmission input element, as well as a flywheel energy storage device for dampening load shocks or fluctuations. On the other hand, the invention relates to a working machine comprising a drive unit with fluctuating power consumption and the aforementioned drive train assembly with the drive unit transmission and the flywheel energy storage device.

[0005] With various working units, fluctuations in load or power consumption can sometimes be so significant that the drive source experiences a substantial change in rotational speed, resulting in an overall jerky operation of the machine, as the drive source itself cannot easily absorb or compensate for such torque surges. For example, various agricultural working units exhibit such large fluctuations in load or power consumption, which can originate from the mechanical design or operating principle of the working unit itself, or be caused by fluctuating external loads.

[0006] Such fluctuations in power consumption resulting from the operating principle are demonstrated, for example, by rectangular balers, in which a pusher is periodically pressed into a pressing chamber to compress the harvested crop into rectangular bales. Similar fluctuations in power consumption resulting from fluctuating external loads are also shown by the chopping drums of forage harvesters or the threshing units of a combine harvester, or even the cutting unit of a round baler when the flow of incoming crop fluctuates significantly.

[0007] Similar fluctuations in power consumption are also known in manufacturing technology for stationary presses whose press ram is driven via a crank mechanism.

[0008] When such implements on agricultural machinery are driven by a tractor's power take-off (PTO) shaft, fluctuations in the tractor's engine speed, induced by the implement's power consumption, not only lead to uneven operation of the implement itself, but also to jerky operation of the tractor, since the tractor's engine serves not only as the PTO drive but also as the drive system. With the aforementioned rectangular balers, this can cause the tractor to dip with each stroke of the baler's ram, which is not only uncomfortable for the driver but can also lead to increased wear on components and reduce engine lifespan.

[0009] To mitigate the effects of load or power consumption fluctuations of the implement on the drive engine, various measures have already been considered. For example, document EP 3 298 872 B1 proposes a control system that detects or predicts fluctuations in the power consumption of the implement. The resulting changes in the drive engine's speed are compensated to achieve a consistently constant tractor speed. This solution does not attempt to prevent or mitigate the drive engine's speed fluctuations caused by the varying power consumption of the implement, but rather compensates for the effect of these fluctuations through intelligent control of the diesel engine.

[0010] Another approach involves incorporating a flywheel energy storage system into the drivetrain that powers the working unit. The kinetic energy of this system mitigates the load and power consumption fluctuations of the working unit and their consequences. For example, such a flywheel energy storage system in the drivetrain of a rectangular baler can smooth out the high energy required at specific points or cyclically when the plug is inserted into the press chamber, thus reducing the impact on the tractor and preventing pitching movements or jerky driving speeds.

[0011] To achieve the best possible smoothing of point-like or cyclical energy fluctuations, the flywheel energy storage system must be able to provide a sufficiently high level of kinetic energy. In principle, increasing the flywheel's mass would be a simple way to achieve this, but this measure is subject to limitations for several reasons. Firstly, the mass itself cannot be increased arbitrarily, as the available installation space is usually limited, and the overall weight must also be considered.

[0012] On the other hand, it has already been considered to increase the kinetic energy of the flywheel energy storage system by increasing its rotational speed, since the kinetic energy of the flywheel energy storage system depends on its angular velocity. More precisely, the angular velocity squares its value in relation to the kinetic energy, according to the formula Ekin = 1 / 2 * J0 * w 2where Jo is the moment of inertia and co is the angular velocity. On the other hand, such an increase in the kinetic energy of the flywheel energy storage system is also limited by the fact that the drive source, for example, the tractor's drive motor, cannot provide the necessary torque to start up the flywheel energy storage system. To address this problem, a slip clutch is sometimes used upstream of the flywheel to gradually introduce the available drive power into the flywheel, thus correspondingly extending the start-up time of the flywheel energy storage system. This gradually brings the flywheel up to the desired target operating speed, preventing the drive motor from stalling. However, such a slip clutch must be adequately dimensioned to absorb the energy generated during the slipping phase, which can be challenging in confined installation spaces.The environmental conditions do not readily permit this.

[0013] Another approach to solving these start-up problems is to operate the flywheel energy storage system via a planetary gear with a variable transmission ratio, in order to adjust the speed of the flywheel energy storage system depending on the operating situation and to gradually increase it when starting up the machine combination by changing the transmission ratio, see for example DE 10 2021 116 061 A1.

[0014] Even though these various approaches mitigate the startup problems and provide a sufficiently high flywheel mass or, through appropriate rotational speed, a sufficiently high kinetic energy from the flywheel energy storage system to smooth out load peaks, previous solutions result in strong, shock-like loads on the transmission components of the drive unit. The high kinetic energy of the flywheel energy storage system, on the one hand, and the shock load from the working unit, on the other, place a correspondingly high load on the drive unit in such existing solutions, as the flywheel energy storage system, with its high kinetic energy, essentially absorbs the load shock from the working unit and keeps it away from the drive source. Such drive units often incorporate a bevel gear stage to create or bridge an angular misalignment between the transmission input shaft and the transmission output shaft, and possibly...To achieve a desired gear ratio, the required speed difference between the transmission input shaft and output shaft can also be achieved through additional transmission elements, such as meshing spur gear pairs, planetary gear stages, further bevel gear stages, or even chain or belt stages. These transmission elements are subjected to high loads and suffer significant wear due to torque and load surges. They must therefore be dimensioned accordingly to withstand these loads permanently, resulting in a relatively high transmission weight and corresponding size.

[0015] In some working units, load shocks occur only within a small range of rotation, and often always within the same range, thus affecting the same teeth of the gearing. For example, ram presses operate with a connecting rod that is articulated to a crank attached to the gearbox output element. The press ram itself always experiences the load shock towards the top dead center of the crank's rotation, so the load shocks are always transmitted via the same pairs of teeth. Similar load shocks within only small angular ranges can also occur in threshing drives or other reciprocating working units.

[0016] The present invention is based on the objective of creating an improved drive train assembly of the aforementioned type, as well as an improved working machine with such a drive train assembly, which avoid the disadvantages of the prior art and advantageously further develop the latter. In particular, the flywheel energy storage system should be able to provide sufficient energy to smooth the power consumption fluctuations of the working unit within a limited installation space, without overloading the unit's transmission or requiring a massive, large design for the working transmission, even when very short load surges occur in the same transmission position. According to the invention, this objective is achieved by a drive train assembly according to claim 1 and a working machine according to claim 21. Preferred embodiments of the invention are the subject of the dependent claims.

[0017] It is therefore proposed to connect the flywheel energy storage system to the drivetrain section leading from the transmission to the driven unit via a branching flywheel train at various engagement points. This splits the flywheel moments and distributes the loads across different engagement points, thus preventing overloads and premature wear at a single engagement point. Simultaneously, the branching flywheel train and the resulting reduction in loads at meshing points such as gear engagement points allow for smaller, lighter, and less robust designs of the flywheel moment-transmitting components. This enables a lightweight and compact overall design of the drive assembly, despite the high flywheel moments.

[0018] According to the invention, the flywheel storage device is connected to the transmission output element of the drive unit, through which the drive unit is connected to the working unit, at two different engagement points via at least two branches of a forking flywheel train, which each transmit a part of the total flywheel torque in parallel to each other.

[0019] In a further development of the invention, at least one of the aforementioned flywheel drive branches is connected on the output side or the transmission output side of the power unit transmission, preferably bypassing all transmission stages of the power unit transmission completely. This allows the aforementioned branch to introduce load impulses from the power unit directly into the flywheel energy storage device without having to transmit the load impulses through the transmission or reduction stages of the power unit transmission. Due to this output-side connection of the flywheel energy storage device, the load impulses are diverted, so to speak, before reaching the power unit transmission, i.e., already at the transmission output side. This prevents the transmission stages of the power unit transmission, such as any bevel gear stage or other reduction gear stages that serve to transmit the drive torque from the drive source, from participating in the transmission of the load impulses.

[0020] The other of the two aforementioned drive branches can be connected to a drive train section located on the driving output side of the power unit transmission, through which the power unit transmission transmits drive torque to the transmission output element. This drive train section is thus designed to transmit both inertial torque and drive torque, and the transmission output element has a common point of engagement for the other of the two drive branches and the power unit transmission. Advantageously, the other drive branch is connected to the drive train section on the output side of the power unit transmission to such an extent that the transmitted inertial torque does not pass through the transmission's reduction or reduction stages, or other stages of the transmission that engage in rolling motion, such as its bevel gear stage, its reduction gear stages, or any intermediate stages.In particular, it is only the transmission output element that must transmit both the inertial torque and the drive torque via a rolling engagement.

[0021] Advantageously, the aforementioned second branch can be connected via one or more spur gear stages to a bevel gear stage, in particular to the output-side bevel gear of the bevel gear stage of the drive unit, so that the moment of inertia may still be transmitted - depending on the connection side - by the aforementioned bevel gear or pass through it, but in any case does not have to be carried away by the rolling engagement of the bevel gears or their teeth.

[0022] In particular, the flywheel energy storage system, along with all branches of the flywheel drive, can engage directly with the aforementioned transmission output element, to which the working unit is also connected. The two different engagement points on the transmission output element can transmit torque in different ways: one engagement point can serve solely to transmit only a portion of the flywheel torque, while the other engagement point can serve to transmit another portion of the flywheel torque and the drive torque coming from the power source.

[0023] The aforementioned transmission output element can be a gear wheel that transmits its rotational speed on the one hand to the working unit or the drive train leading to the working unit, and on the other hand to the flywheel energy storage device or to the branches of the flywheel drive leading to the flywheel energy storage device. The flywheel energy storage device and the working unit are thus connected to the same gear wheel and to the same output speed of the gear wheel. However, the flywheel energy storage device and the working unit do not necessarily have to operate at the same speed or frequency, since at least one further gear stage can preferably be provided in the flywheel drive leading to the flywheel energy storage device in order to, for example, increase the rotational speed of the flywheel energy storage device and generate a correspondingly high kinetic energy.

[0024] In particular, the aforementioned transmission output element of the aggregate transmission can drive a crank leading to the working unit or drive a crank which, via a connecting rod, drives the working tool of the working unit, for example the tamping piston of an agricultural harvesting machine or the press ram of a tethered press in forming technology.

[0025] The two branches of the flywheel drive can be connected to the aforementioned crank wheel, i.e., the gear wheel acting as the transmission output element, which drives the aforementioned crank. Advantageously, these connections can be made in two separate sectors of the gear wheel and / or to two or more than two separate teeth of the gear wheel in order to distribute the loads over at least two points of engagement. To prevent the shock loads from the working unit or the intermittently pulsating power flow between the working unit and the flywheel energy storage system from passing through the gear stages of the power unit transmission, a further development of the invention involves combining or branching off two separate drive trains on the transmission output side. On the one hand, the drive train that leads through the power unit transmission to the drive source, for example, the power take-off shaft or the tractor's drive motor, is connected to the aforementioned transmission output element.On the other hand, the separate flywheel train, which leads to the flywheel energy storage system, is connected to the aforementioned transmission output element. If the aforementioned flywheel train is split or branched into several strands, three or more torque-transmitting strands are even brought together at the aforementioned output-side transmission element.

[0026] In a further development of the invention, the two branches of the flywheel train can be parts of a planetary gear set and / or be joined together by a planetary gear set to form the common flywheel train leading to the flywheel storage unit.

[0027] Advantageously, the flywheel energy storage system is connected to a comparatively faster rotating planetary gear shaft, while the two drive branches are each connected to a comparatively slower rotating planetary gear shaft. Since rotational energy increases quadratically with rotational speed, this distribution of the planetary gear elements and / or connection of the flywheel energy storage system allows for high efficiency of the flywheel energy storage system even with smaller dimensions.

[0028] In particular, the flywheel energy storage device can be connected to the comparatively faster rotating sun gear, one of the two strand branches to the comparatively slower rotating planet carrier, and the other of the two strand branches to the ring gear of the planetary gear.

[0029] When the flywheel energy storage system is connected to a rapidly rotating shaft, such as the aforementioned sun gear shaft, the flywheel energy storage system can be built so small that it can be accommodated in the gearbox housing without requiring an excessively large housing.

[0030] Alternatively, the flywheel energy storage device can also be arranged externally or outside the gearbox housing, whereby in this case, encapsulation of the flywheel energy storage device can also be advantageous in order to reduce noise and risk of injury and to provide protection against dirt and the like.

[0031] The branch connected to the planet carrier can be the branch that bypasses all gear stages of the drive unit and is connected to the transmission output element on the output side of the drive unit, and has a point of engagement on the transmission output element that differs from the point of engagement of the drive train section coming from the drive unit.

[0032] In particular, the drive branch that transmits a comparatively larger part of the inertial torque can bypass all gear stages of the drive unit and be connected to the transmission output element on the output side of the drive unit, and have a point of engagement on the transmission output element that differs from the point of engagement of the drive train section coming from the drive unit.

[0033] Alternatively or additionally, the drive branch connected to the ring gear can be connected to the drive train section located on the output side of the drive unit, through which the drive unit transmits drive torque to the transmission output element. Preferably, the drive branch connected to the ring gear can be connected to the output-side bevel gear of the bevel gear stage of the drive unit via one or more spur gear stages.

[0034] Regardless of this, the two drive shafts and / or the connected planetary gear shafts, in particular the planet carrier on the one hand and the ring gear on the other, can have different rotational speeds and / or opposite directions of rotation. This can result in a significant increase in the rotational speed of the sun gear shaft or the flywheel accumulator. At the same time, different directions of rotation can also be advantageous with regard to smooth running, as any imbalances can at least partially compensate for each other or do not act simultaneously in the same direction.

[0035] Alternatively, it is also possible to design the planetary gear in such a way that both drive branches or ring gear and planet carrier have the same direction of rotation and / or the same speed.

[0036] Preferably, the two strands are designed such that the flywheel storage device runs at a higher speed than the aforementioned transmission output element.

[0037] Regardless of this, the two strands can be designed to transmit different high inertial torques to each other, each forming a part of the total inertial torque and / or adding up to the total inertial torque.

[0038] Preferably, the aforementioned two branches of the flywheel train can each be in end-to-end engagement with the transmission output element designed as a gear wheel and can branch off from the transmission output element in different sectors, in particular from different sides or on opposite sides.

[0039] The two mentioned points of engagement of the flywheel train with the transmission output element designed as a gear wheel can each be end-contact points, whereby the mentioned points of engagement can be arranged in different sectors, for example on opposite sides or in adjacent sectors, of the gear wheel.

[0040] Other engagement configurations or hybrid configurations, such as conical engagement on the one hand and face engagement on the other, would be conceivable. However, the aforementioned design with face-engaging drive branches is advantageous in terms of its compact construction and the simple design of the gear wheel that serves as the transmission output element.

[0041] In particular, the two branches of the flywheel train or their connecting elements can be in tooth mesh with the aforementioned gear wheel.

[0042] The planetary gear mentioned can be single-stage or multi-stage. An additional reduction gear stage within the planetary gear allows the flywheel energy storage system to operate at a potentially significantly higher speed, thereby generating sufficient kinetic energy to adequately smooth the torque and load surges of the working unit.

[0043] To enable the flywheel energy storage system to spin up even with only limited torque available from the drive source, and in particular to the intended high flywheel speeds, a starting aid for starting the flywheel energy storage system can be provided in a further development of the invention. In a further development of the invention, such a starting aid can comprise a motor to assist the starting process, for example a hydraulic motor or, in particular, an electric motor.

[0044] Such a starting auxiliary motor can advantageously be directly assigned to the flywheel energy storage system's flywheel mass train and / or provided on the output side of the drive unit's transmission, so that the starting torque of the starting motor does not have to be transmitted via the drive unit's transmission to start the flywheel energy storage system.

[0045] For example, such a starting motor can be connected to one of the three shafts of the planetary gear set. Depending on its design, the starting motor can be configured for relatively low torque and high speeds, and such a motor can be connected, for instance, to the sun gear of the planetary gear set or a sun gear shaft. Alternatively, a starting motor with relatively high torque and lower speeds can be used, and such a motor can preferably be connected to the planet carrier or the ring gear of the aforementioned planet gear set. Connection to an intermediate gear is also possible if this is advantageous due to space constraints or accessibility.

[0046] Preferably, the starting aid is designed such that the starting motor is only active or in operation while the flywheel energy storage system is ramping up. Advantageously, an overrunning freewheel can be provided so that the starting motor can be switched off after the flywheel energy storage system has ramped up. An overrunning freewheel provided between the motor and the flywheel energy storage system transmits torque in one direction of rotation and is free-running in the opposite direction, so that during ramping up the system, the motor can drive the flywheel energy storage system along with it, while once the flywheel energy storage system has ramped up, the motor can be switched off without being driven by the flywheel energy storage system.

[0047] The invention is explained in more detail below with reference to preferred embodiments and accompanying drawings. The drawings show:

[0048] Fig. 1: a schematic representation of a drive train assembly for driving the working tool of a machine with a flywheel storage device connected on the output side via a separate flywheel train, wherein the flywheel train is branched into two branches by means of a planetary gear and is connected to the drive train leading to the working tool at two separate engagement points.

[0049] Fig. 2: a side view of the drive train assembly from Figure 1, showing the arrangement of the elements of the assembly relative to each other and in particular the connection of the flywheel train branches to the gearbox output spur gear in different sectors; Fig. 3: a schematic representation of a drive train assembly according to a further embodiment of the invention in a view similar to Figure 1, wherein the flywheel storage device is arranged outside the gearbox housing, unlike in Figure 1.

[0050] The drive train assembly shown in the figures can be connected to a working machine 1 (only indicated) or serve to drive its working tool, which may be an agricultural machine for processing crops or possibly also for soil cultivation, e.g., in the form of an implement for mounting on an agricultural or forestry tractor. However, the working machine may also be designed in a different way, with the assembly being particularly advantageous for working tools with more fluctuating drive torque.

[0051] Such a machine comprises at least one working unit 3, which may be subject to highly fluctuating loads during operation and / or may exhibit highly fluctuating power consumption. For example, the machine 1 may be designed as a baler, whose working unit 3 may include a pusher that enters a baling chamber or is moved cyclically back and forth within it to compress harvested crops, which have been conveyed into the baling chamber via a suitable conveying device, into bales.

[0052] The working unit 3 is driven by the mechanical drive train assembly 12, which may include a cardan shaft 11, which can be connected in a rotationally fixed manner to a drive source 10 such as the power take-off shaft of the tractor and can be driven by the tractor's drive motor, for example a diesel engine.

[0053] The aforementioned drive train assembly 12 comprises a drive unit 6, which can be connected to the drive source, such as the cardan shaft 11 and thus to the engine of the tractor, via a transmission input element 15, wherein the aforementioned transmission input element 15 can be an input shaft of the drive unit 6.

[0054] The transmission output element 14 of the assembly transmission 6, which forms the output side or output element of the aforementioned assembly transmission 6, can be a crankshaft 7 which drives the working tool, such as the plunger of the working unit 3, back and forth via a connecting rod 8.

[0055] As the figures show, the aforementioned drive unit 6 can comprise one or more gear stages between its input and output elements 15, 14, which can be configured as transmission or reduction stages. In particular, the drive unit 6 can comprise a bevel gear stage 24, which can drive the output element 14, in particular the aforementioned crankshaft 7, directly or via an intermediate stage 25. The intermediate stage 25 can, for example, be a spur gear stage, see Figures 1, 2 and 3.

[0056] In particular, the transmission output element 14 can have a gear wheel 26, preferably a spur gear, which may be designed as a spur-toothed pinion, wherein said gear wheel 26 is mounted on the crankshaft 7 and is thus non-rotatably connected to it. The gear wheel 26 can be driven from the aforementioned intermediate stage 25 by the drive source 10, that is, the drive train 9 connected to the drive source 10, e.g., in the form of the power take-off shaft of a tractor, drives the output gear 26 with the drive power of the drive source 10 via the driveshaft 11 and the drive unit 6. This gear wheel then drives the crankshaft 7 rotationally and thus drives the working tool in a reciprocating motion.

[0057] As the figures further show, a flywheel storage device 13 is connected to the output side of the drive unit 6 via a flywheel train SM13, wherein the flywheel train SM13 driving the flywheel storage device 13 or vice versa being driven by it can in particular be connected to the transmission output element 14 of the drive unit 6 in the form of the gear wheel 26, so that the kinetic energy coming from the flywheel storage device 13 can be given directly to the crankshaft gear wheel 26 to smooth out load shocks of the plugger 4.

[0058] The aforementioned flywheel string 13 splits into at least two branches SZ1 and SZ2, as shown in Figures 1 and 3, through which a part of the total flywheel moment of the flywheel storage unit 13 is transmitted.

[0059] The strand branches SZ1 and SZ2 split by means of a planetary gear PG, or the strand branches are joined together by the aforementioned planetary gear PG, which - depending on the direction of view - divides the total flywheel moment between the strand branches SZ1 and SZ2, or combines their partial moments to form the total flywheel moment and applies it to the flywheel storage device 13.

[0060] As shown in Figures 1 and 3, the flywheel assembly SM13, or its branches SZ1 and SZ2, is connected to the transmission output gear 26, which can be a crankshaft gear, via at least two engagement points EP1 and EP2, for example, in the form of gear meshes. The torque distribution is achieved via the aforementioned planetary gear PG, which can be configured with three free shafts. A differential shaft, for example, in the form of the sun gear shaft connected to the sun gear SR, is preferably connected to the reduced-size, high-speed flywheel, which can be designed to be reduced in size and high-speed due to this connection.

[0061] A first point of engagement EP 1, for example in the form of a tooth engagement of the crankshaft gear 26, is preferably connected to the sum shaft, for example in the form of a web shaft of the planetary gear PG connected to the planet carrier PT, see Fig. 1 and 3 as well as Fig. 2.

[0062] A second point of engagement EP2, which can again be a tooth engagement with the crankshaft gear 26, is connected via a spur gear chain or one or more spur gear stages and via the bevel gear set of the drive unit 6 to the ring gear HR or a ring gear shaft connected thereto to the planetary gear PG, cf. Figs. 1 and 3 as well as Fig. 2. The still free sun gear shaft, which forms a differential shaft, is advantageously connected, as mentioned, to the flywheel of the flywheel energy storage unit 13. Since the rotational energy increases quadratically with the rotational speed, the fast-rotating sun gear shaft is advantageously connected to the flywheel.

[0063] Thus, on the transmission output gear 26 or crankshaft gear, there are two engagement points EP1 and EP2 for the flywheel train SM13 or its train branches SZ1 and SZ2, which can be designed as rolling engagements, in particular in the form of tooth engagements or possibly also as friction wheel engagements.

[0064] Each point of engagement EP 1 and EP2, or their tooth or rolling engagements, can thus be adjusted in terms of torque by dividing the gear ratios - in particular by appropriate design of the planetary gear PG and its interacting elements in the form of sun gear SR, planet P, planet carrier PT and ring gear HR.

[0065] The multiple drive branches SZ1 and SZ2, and the multiple engagement points EP1 and EP2, reduce the loads on the meshing teeth or gear element sections, allowing the components of the assembly to be made smaller. The planetary gear PG distributes the torques or inertial moments and essentially acts as a differential gear. Constraints and overdetermination are advantageously eliminated.

[0066] The spur gear chain, or the one or more spur gear stages SRS provided in the second branch SZ2, can be designed such that the directions of rotation of the planet carrier PT and the ring gear HR of the planetary gear PG, and thus the directions of rotation of the two branches SZ1 and SZ2, are opposite, resulting in a significant increase in rotational speed at the sun gear shaft. By adjusting the gear ratio of the one or, if necessary, several planetary stages of the planetary gear PG, the rotational speed of the flywheel can be optimized. By increasing the rotational speed of the flywheel, its dimensions can be significantly reduced while maintaining the same rotational energy.

[0067] The spur gears 29 and 28 of the spur gear stages 27 and 25, cf. Figures 1 and 3, via which the first branch SZ1 of the flywheel train SM13 on the one hand and the drive train 9 on the other hand are connected to the output-side crankshaft gear wheel 26, can engage with the said gear wheel 26 in various circumferential sections, cf. Fig. 2, for example, arranged on opposite sides of the gear wheel 26 or also arranged in adjacent sectors of the gear wheel 26, cf. Figure 2, whereby an overall compact design of the drive unit 6 can be achieved.

[0068] For example, the two mentioned spur gears 28, 29 can both engage with a lower circumferential half of the crankshaft gear wheel 26, so that the drive unit 6 and the flywheel storage 13 can be arranged below the crankshaft 7, see Figure 2, resulting in an overall compact and economical design.

[0069] As can be seen from the figures, one of the at least two points of engagement EP1 serves solely to transmit a part of the inertial moment and another of the at least two points of engagement EP2 serves to transmit a further part of the inertial moment and the drive torque coming from the drive source 10.

[0070] At least one of the two mentioned drive branches SZ1 can be connected to the transmission output element 14 on the output side of the drive unit 6, bypassing the drive unit 6, while a drive train section AS6 coming from the drive unit 6 can have an engagement point EP2 on the transmission output element 14, which is different from the engagement point EP1 of the mentioned at least one drive branch SZ1.

[0071] The other of the two mentioned drive branches SZ2 can be connected to the drive train section AS6, which is located on the output side of the drive unit 6 and via which the drive unit transmits drive torque to the transmission output element 14, so that the said drive train section AS6 is designed to transmit both flywheel torque and drive torque and the transmission output element 14 has a common engagement point EP2 for the other of the two drive branches SZ2 and the drive unit 6.

[0072] In particular, the aforementioned second branch SZ2 can be connected via one or more spur gear stages to a bevel gear stage 24, in particular to the output-side bevel gear 24A of the bevel gear stage 24 of the drive unit 6.

[0073] The transmission output element 14 is in particular a gear wheel 26, which on the one hand drives a crankshaft 7 leading to the working unit 3 and the connecting rod 8 connected thereto and on the other hand engages with the two drive branches SZ1, SZ2 from the flywheel storage unit 13 as well as the drive train AS coming from the drive source 10 and passing through the unit transmission 6 at two separate engagement points EP1, EP2, so that the two drive branches SZ1, SZ2 of the flywheel drive SM13 and the drive train AS coming from the drive source 10 are brought together at the aforementioned gear wheel of the transmission output element 14.

[0074] Advantageously, the two strands SZ1, SZ2 are parts of a single- or multi-stage planetary gear PG and / or are joined by a single- or multi-stage planetary gear PG to form the common flywheel strand SM13 leading to the flywheel storage unit 13.

[0075] Advantageously, the flywheel energy storage device 13 is connected to a comparatively faster rotating planetary gear shaft, and the two drive branches SZ1 and SZ2 are each connected to a comparatively slower rotating planetary gear shaft. Specifically, the flywheel energy storage device 13 can be connected to the comparatively faster rotating sun gear SR, one of the two drive branches SZ1 to the comparatively slower rotating planet carrier PT, and the other of the two drive branches SZ1 and SZ2 to the ring gear HR of the planetary gear PG. The drive branch SZ1 connected to the planet carrier PT can be connected entirely bypassing the drive unit to the transmission output element (14), and the second drive branch SZ2, together with the drive train section AS6 coming from the drive unit 6, can be connected to the transmission output element 14.Preferably, the second branch SZ2 connected to the ring gear HR can be connected to the drive train section AS6, in particular via one or more spur gear stages SRS to the output-side bevel gear 24A of the bevel gear stage of the drive unit (6).

[0076] Advantageously, the flywheel storage unit 13, including its flywheel mass, can preferably be housed entirely inside the gearbox housing GG of the drive unit 6, see Fig. 1. This not only results in an overall compact design, but also in the encapsulation of the flywheel storage unit 13.

[0077] Alternatively, the flywheel energy storage device 13, at least partially, and in particular its flywheel mass, can also be arranged outside the gearbox housing GG, see Fig. 3. In this case, a separate encapsulation can be provided to protect the flywheel energy storage device 13 from contamination and the machine operator from injury.

[0078] In order to be able to start up the flywheel storage device 13, which operates at high speeds, even if the drive source 10 can only provide a limited starting torque, a starting aid can be provided for starting the flywheel storage device 13, wherein said starting aid can have a starting motor, for example an electric motor EM, wherein said starting motor can be connected to or engaged with the sun gear SR of the planetary gear PG, for example, in order to drive the sun gear shaft and thus the flywheel storage device 13.

[0079] In order to be able to switch off the starting motor during the intended operation of the drive train assembly, such a starting motor can be connected to the flywheel storage via an overrunning freewheel, which carries the flywheel storage 13, in particular the sun gear SR, during starting, but on the other hand allows the starting motor, for example the sun gear SR, to rotate faster than the starting motor or can also rotate when the starting motor is stationary.

[0080] The described design of the drive train assembly 12 offers several advantages, particularly when driving machinery or tools with significant torque fluctuations: The arrangement of two pinions or pinion shafts on the crankshaft main gear 26 in the output spur gear stage allows the peak load from the crankshaft drive to be distributed across multiple gear engagements. Consequently, components can be made smaller, which significantly reduces the manufacturing costs of the large gear, i.e., the transmission output gear or crankshaft gear 26. The number of teeth on the pinions 28 and 29 engaging with the crankshaft main gear 26 can be the same or different. Different numbers of teeth result in exceptionally smooth running.• Different torques resulting from the gear ratio of the planetary gear set PG and the spur gear stage can be compensated for by the spur gear stage SRS with the same or different pinion tooth counts. • Using identical parts is advantageous when the pinion shafts are of the same design. • The planetary gear set PG can be optimized for load balancing and speed adjustment. • Optimization of the torques at the pinions or pinion shafts is possible by selecting the gear ratio on the carrier and / or the ring gear. • Equal distribution of torques on the pinion shaft is possible. • The planetary gear set with three free shafts ensures a torque distribution without overdetermination (differential). • The directions of rotation of the carrier and ring gear can be designed to be opposite, for high sun gear speed and thus high rotational energy. • The planetary gear set can also be built with multiple stages for even higher gear ratios.The flywheel / rotor arrangement allows for high flywheel masses despite small dimensions and compact housing. The flywheel rotates with a rapidly rotating shaft, enabling high rotational energy through high rotational speed. The flywheel can be much smaller than when mounted on the input shaft and can be easily encapsulated or integrated into the gearbox housing. Disturbances caused by air movement are reduced when the flywheel is encapsulated and / or located inside the gearbox housing. Encapsulation or integration into the gearbox housing prevents potential hazards to life and limb. The lower mass of the flywheel allows for a lighter overall drivetrain that does not increase the total machine weight. Increased rotational energy can also be achieved with a larger flywheel mass, resulting in smoother operation of the working tool.• Increasing the rotational speed of the flywheel allows for a reduction in the size of the slip clutch in terms of its compressive torque, as well as the safety overload clutch, while maintaining the same rotational energy. • Alternatively, for better accessibility, the flywheel can also be mounted externally on the gearbox. • The intermediate spur gear stage can also be advantageous and optimized for various purposes. • In particular, distributing the torque / power between the two spur gear stages at the output can be easily achieved. • Setting the ring gear and planet carrier to rotate in opposite directions allows for an increase in the rotational speed of the sun gear shaft, on which the flywheel is also mounted. • The rotation can also be synchronous: The ring gear and planet carrier can work together with an intermediate gear to reduce the rotational speed of the sun gear and utilize a larger flywheel.• Adjustments to the center distances between the spur gear stages at the output are ideally achieved with this design. This increases the available design freedom. • A multiple arrangement of a pinion shaft pair with load balancing via a planetary gear set can be distributed around the circumference of the crankshaft gear. • The modular design allows for adaptation to different power outputs using the same components. • Shifting processes can be optimized by cascaded engagement of the flywheels. • The oil supply can be optimized, particularly by integrating the components into a common gearbox housing.

Claims

3182-25 T / wb Liebherr-Components Biberach GmbH Drivetrain assembly for powering a work unit with a fluctuating load Claims 1. Drive train assembly for driving a working unit (3) with fluctuating power input from a drive source (10), comprising a drive unit transmission (6) that converts a drive movement of the drive source (10) into a working movement of the working unit (3) and is connected to the working unit (3) via a transmission output element (14) and to the drive source (10) via a transmission input element (15), and a flywheel storage device (13) for mitigating load shocks and / or power input fluctuations, characterized in that the flywheel storage device (13) is connected to the transmission output element (14) at at least two different engagement points (EP1, EP2) via at least two branches (SZ1, SZ2) of a forking flywheel train (SM13), which transmit flywheel torque in parallel to each other.

2. Drivetrain assembly according to the preceding claim, wherein one of the at least two engagement points (EP1) is solely for transmitting a portion of the inertial torque and another of the at least two engagement points is for transmitting a portion of the inertial torque. points (EP2) are provided for the transmission of another part of the inertial moment and the drive torque coming from the drive source (10).

3. Drive train assembly according to one of the preceding claims, wherein at least one of the two said drive train branches (SZ1 ) is connected to the transmission output element (14) on the output side of the transmission (6) and a drive train section (AS6) coming from the transmission (6) has an engagement point (EP2) on the transmission output element (14) which is different from the engagement point (EP1 ) of the said at least one drive train branch (SZ1 ).

4. Drivetrain assembly according to the preceding claims, wherein the other of the two said drive branches (SZ2) is connected to the drivetrain section (AS6) which is located on the output side of the drive unit (6) and through which the drive unit transmits drive torque to the transmission output element (14), such that the said drivetrain section (AS6) is designed to transmit both flywheel torque and drive torque and the transmission output element (14) has a common engagement point (EP2) for the other of the two drive branches (SZ2) and the drive unit (6).

5. Drive train assembly according to the preceding claim, wherein the other of the two train branches (SZ2) is connected via one or more spur gear stages to a bevel gear stage, in particular to the output-side bevel gear (24) of the bevel gear stage, of the drive unit (6).

6. Drivetrain assembly according to one of the preceding claims, wherein the transmission output element (14) is a gear wheel which, on the one hand, drives a crankshaft (7) leading to the working unit (3) and, on the other hand, engages with the two drive branches (SZ1, SZ2) from the flywheel storage unit (13) and the drive train (AS) coming from the drive source (10) and passing through the unit transmission (6), such that the two drive branches are engaged at the said gear wheel of the transmission output element (14). (SZ1 , SZ2) of the flywheel train (SM13) and the drive train (AS) coming from the drive source (10) are joined together.

7. Drive train assembly according to one of the preceding claims, wherein the two engagement points (EP1 , EP2) are face engagement points in different spur gear sectors, in particular face gear points on different teeth, on the transmission output element (14) designed as a spur gear.

8. Drive train assembly according to one of the preceding claims, wherein the two train branches (SZ1 , SZ2) are parts of a single- or multi-stage planetary gear unit (PG) and / or are joined by a single- or multi-stage planetary gear unit (PG) to the common flywheel assembly (SM13) leading to the flywheel storage unit (13).

9. Drive train assembly according to the preceding claim, wherein the flywheel storage device (13) is connected to a comparatively faster rotating planetary gear shaft and the two drive train branches (SZ1 , SZ2) are each connected to a comparatively slower rotating planetary gear shaft.

10. Drive train assembly according to the preceding claim, wherein the flywheel storage device (13) is connected to the comparatively faster rotating sun gear (SR), one of the two train branches (SZ1 , SZ2) to the comparatively slower rotating planet carrier (PT) and the other of the two train branches (SZ1 , SZ2) to the ring gear (HR) of the planetary gear (PG).

11. Drivetrain assembly according to the preceding claim in conjunction with one of claims 3 and 4 or one of the claims relating thereto, wherein the drive branch (SZ1) connected to the planet carrier (PT) is connected past the drive unit transmission on the output side of the drive unit transmission (6) to the transmission output element (14) and has the point of engagement (EP1) on the transmission output element (14) different from the point of engagement (EP2) of the drivetrain section (AS6) coming from the drive unit transmission (6).

12. Drive train assembly according to one of the preceding claims, wherein the drive branch (SZ2) connected to the ring gear (HR) is connected to the drive train section (AS6) which is located on the output side of the drive unit (6) and via which the drive unit transmits the drive torque coming from the drive source (10) to the transmission output element (14).

13. Drive train assembly according to the preceding claim in conjunction with claim 5 or one of the claims relating thereto, wherein the drive branch (SZ2) connected to the ring gear (HR) is connected via one or more spur gear stages to the output-side bevel gear (24) of the bevel gear stage of the drive unit (6).

14. Drive train assembly according to one of the preceding claims, wherein the two train branches (SZ1 , SZ2) have different rotational speeds and / or opposite directions of rotation.

15. Drive train assembly according to one of the preceding claims, wherein the two train branches (SZ1 , SZ2) are configured to transmit different high inertial torques, each forming a part of the total inertial torque and / or summing up to the total inertial torque.

16. Drive train assembly according to the preceding claim, wherein the first and second branches (SZ1 , SZ2) of the flywheel train (SM13) are each in end mesh with the transmission output element (14) designed as a gear wheel (26) and extend from the transmission output element (14) in different sectors, in particular on opposite or adjacent sides.

17. Drive train assembly according to one of the two preceding claims, wherein at least one of the two branches (SZ1 , SZ2) of the flywheel train (SM13) each has at least one or more transmission / reduction gear stages, in particular in the form of one or more spur gear stages (SRS) in addition to the planetary gear (SZ).

18. Drive train assembly according to one of the preceding claims, wherein the two train branches (SZ1 , SZ2) are configured such that the flywheel storage device (13) operates at a higher speed than the transmission output element (14).

19. Drive train assembly according to one of the preceding claims, wherein the flywheel storage device (13) is arranged inside the gearbox housing (GG) of the drive unit (6).

20. Drive train assembly according to one of the preceding claims, wherein the drive unit (6) has at least one bevel gear stage (24) and at least one intermediate gear stage between its transmission input element (15) and its transmission output element (14).

21. Working machine with a drive train assembly (12) designed according to one of the preceding claims.

22. Working machine according to the preceding claim, the working unit (3) of which has a working tool which can be driven back and forth by a crankshaft (7).

23. Working machine according to one of the two preceding claims, which is designed as an agricultural harvesting or soil cultivation machine, in particular as a rectangular baler.

24. Working machine according to one of claims 21 to 23, which is designed as an attachment for mounting on a towing vehicle and whose working unit (3) can be coupled to the drive source (10) located on the towing vehicle via the said drive train assembly (12).

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