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

Abstract

The present invention relates to a drive train assembly for driving a working unit with fluctuating power consumption from a drive source, with a unit transmission which converts a driving movement of the drive source into a working movement of the work unit and is connected by a transmission output element to the working unit and is connected by a transmission input element to the drive source, and with a flywheel accumulator for mitigating load impacts and / or power consumption fluctuations, wherein the flywheel accumulator is connected on the output side of the unit transmission to the drive train which runs from the unit transmission to the working unit.

Description

[0001] Drive train assembly for driving a working unit with fluctuating load

[0002] The present invention generally relates to work machines with work units that are subject to fluctuating loads or have a fluctuating power consumption. The invention relates, on the one hand, to a drive train assembly for driving such a work unit with fluctuating power consumption from a power source, with an assembly gearbox that converts a drive movement of the drive source into a work movement of the work unit and is connected, on the one hand, to the work unit via a gearbox output element and, on the other hand, to the drive source via a gearbox input element, as well as a flywheel accumulator for mitigating load surges or fluctuations. The invention also relates to a work machine that comprises a drive unit with fluctuating power consumption and the aforementioned drive train assembly with the assembly gearbox and the flywheel accumulator.

[0003] Various work units sometimes experience such significant fluctuations in load or power consumption that the drive unit experiences a significant change in speed, resulting in overall jerky operation of the machine, as the drive unit itself cannot easily absorb or compensate for such torque surges. For example, various agricultural work units exhibit such significant fluctuations in load or power consumption, which can arise from the mechanical design or operation of the work unit itself, or can also be caused by fluctuating external loads.

[0004] Such operating-related fluctuations in power consumption are evident, for example, in rectangular balers, where a pusher is periodically pushed into a baling chamber to compress the crop into rectangular bales. Similar power consumption fluctuations resulting from fluctuating external loads are also exhibited by the chopper drums of forage harvesters or the threshing units of a combine harvester, or even the cutting unit of a round baler when the incoming crop flow fluctuates significantly.

[0005] Similar fluctuations in power consumption are also known in manufacturing technology for path-bound presses whose press ram is driven by a crank gear.

[0006] If such working units of agricultural machinery are driven by a tractor via a PTO, speed fluctuations in the tractor's drive engine, which are induced by fluctuations in the power consumption of the working unit, not only lead to uneven operation of the working unit itself, but also to jerky operation of the tractor, since the tractor's drive engine serves not only as a PTO drive but also as a travel drive. In the case of the rectangular balers mentioned, this can result in the tractor nodding with each ram stroke of the baler, which is not only unpleasant for the driver but can also lead to increased wear on the components and shorten the engine life. Various measures have already been considered to mitigate the effects of load or power consumption fluctuations of the working unit on the drive motor.For example, document EP 3 298 872 B1 proposes a control system that detects or predictively estimates fluctuations in the power consumption of the working unit. The speed changes of the drive motor are compensated to ultimately achieve a constant driving speed of the tractor. This solution does not even attempt to prevent or mitigate the speed fluctuations of the drive motor caused by the fluctuating power consumption of the working unit, but rather compensates for the effect of the speed fluctuations of the drive motor through intelligent control of the diesel engine.

[0007] Another approach involves installing a flywheel accumulator in the drive train that powers the working unit. Its kinetic energy dampens the load or power consumption fluctuations of the working unit and their consequences. For example, such a flywheel accumulator in the drive train of a rectangular baler can smooth out the high energy required at specific points or in cycles when inserting the stuffer into the baling chamber, thus mitigating the impact on the tractor and preventing pitching movements or jerky driving speeds.

[0008] However, to achieve the best possible smoothing of occasional or cyclical energy fluctuations, the flywheel storage system must be able to provide sufficiently high kinetic energy. This would be simple to achieve simply by increasing the flywheel storage system's inertia, although this measure is subject to limitations for various reasons. On the one hand, the inertia itself cannot be increased indefinitely, as the available installation space is usually limited, and the overall weight must also be considered.

[0009] In this respect, it has already been considered to increase the kinetic energy of the flywheel storage by increasing its speed, since the kinetic energy of the flywheel storage depends on its angular velocity. More precisely, the angular velocity is squared in the kinetic energy, according to the formula Ekin=1 / 2*J0*w 2 , where J ois the moment of inertia and co is the angular velocity.

[0010] On the other hand, such an increase in the kinetic energy of the flywheel 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 storage system. To counteract this problem, a slip clutch is sometimes used upstream of the flywheel to gradually transfer the available drive power to the flywheel, thereby extending the start-up time of the flywheel storage system accordingly. The flywheel is thus gradually brought up to the desired target operating speed so that the drive motor is not stalled. However, such a slip clutch must be sufficiently dimensioned to be able to absorb the energy generated during the slipping time, which is not easily possible in cramped installation or environmental conditions.

[0011] Another approach to solving these start-up problems is to operate the flywheel storage system via a planetary gear with a variable gear ratio in order to be able to adapt the speed of the flywheel storage system depending on the operating situation and to gradually increase it when starting up the machine combination by adjusting the gear ratio, see for example DE 10 2021 116 061 A1.

[0012] Even if these various approaches can alleviate the startup problem and provide a sufficiently high flywheel mass or, through appropriate speed, a sufficiently high kinetic energy of the flywheel storage system to smooth out load peaks, previous solutions still result in strong, shock loads on the transmission elements of the unit's gearbox. The high kinetic energy of the flywheel storage system, on the one hand, and the shock load from the working unit, on the other, place a correspondingly high load on the unit's gearbox in such previous solutions, as the flywheel storage system, with its high kinetic energy, effectively absorbs the load surge of the working unit and keeps it away from the drive source.

[0013] Such aggregate transmissions often feature a bevel gear stage to generate or bridge an angular misalignment between the transmission input shaft and the transmission output shaft, and possibly also to achieve a desired gear ratio. The desired speed difference between the transmission input shaft and the transmission output shaft can also be achieved using additional transmission elements, for example, in the form of meshing spur gear pairs, planetary gear stages, additional bevel gear stages, or even chain or belt stages. These transmission elements are subject to heavy loads and suffer significant wear due to torque or load surges, or they must be dimensioned accordingly to be able to permanently dissipate the loads. This results in a relatively high transmission weight and correspondingly high overall size.

[0014] With some working units, the load shocks occur only within a small range of rotation angles and often always within the same range of rotation angles, thus affecting the same teeth of the gearing. For example, ram presses operate with a connecting rod connected to a crank attached to the gearbox output element. The press ram always experiences the load shock toward the top dead center of the crank's rotational movement, 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.

[0015] Based on this, the present invention is based on the object of creating an improved drive train assembly of the aforementioned type and an improved work machine with such a drive train assembly, which avoid the disadvantages of the prior art and advantageously develop the latter. In particular, the flywheel storage device should be able to provide sufficient energy to smooth the power consumption fluctuations of the work unit in limited installation space, without overloading the unit's transmission or requiring a massive, large design of the work transmission, even when very short-term load surges occur in the same transmission position.

[0016] According to the invention, the stated object is achieved by a drive train assembly according to claim 1 and a work machine according to claim 15. Preferred embodiments of the invention are the subject of the dependent claims.

[0017] It is therefore proposed to connect the flywheel accumulator to the output side or the transmission output side of the aggregate gearbox, so that load surges from the working unit can be introduced into the flywheel accumulator or compensated by the flywheel accumulator without having to transmit the load surges through the aggregate gearbox. By connecting the flywheel accumulator to the output side, the load surges are diverted, so to speak, before reaching the aggregate gearbox or already at the transmission output side, leaving the gear stages of the aggregate gearbox, such as any existing bevel gear stage or intermediate pinion stages, unloaded, or essentially only the power coming from the drive shaft is transmitted by the aggregate gearbox, while the high load surges from the working unit are essentially guided past the aggregate gearbox into the flywheel accumulator or are compensated by it.

[0018] According to the invention, the flywheel accumulator is connected on the output side of the aggregate transmission to the drive train that runs from the aggregate transmission to the working unit. The flywheel accumulator or a connecting element driving the flywheel accumulator engages with a drive train element that is arranged on the output side of the aggregate transmission or is directly coupled to the drive train that runs from the aggregate transmission to the working unit. By connecting the flywheel accumulator on the transmission output side, the kinetic energy of the flywheel accumulator can be guided past the aggregate transmission or past the gear stages of the aggregate transmission directly into the working unit. In particular, the flywheel accumulator orthe connecting element of the drive train leading to the flywheel accumulator which drives the flywheel accumulator is directly engaged with the said transmission output element, to which the working unit is also connected at the same time.

[0019] The aforementioned transmission output element can be a gear wheel that transmits its speed to the working unit or the drive train leading to the working unit, on the one hand, and to the flywheel storage unit or the drive train leading to the flywheel storage unit, on the other hand. The flywheel storage unit 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 storage unit and the working unit do not necessarily have to operate at the same speed or frequency, since, for example, there can be an additional gear stage in the drive train leading to the flywheel storage unit, for example, to increase the speed of the flywheel storage unit and generate a correspondingly high kinetic energy.

[0020] In particular, the said transmission output element of the aggregate transmission can drive a crank leading to the working aggregate or a crank which, via a connecting rod, drives the working tool of the working aggregate, for example the tamping piston of an agricultural harvesting machine or the press ram of a path-bound press in metal forming technology.

[0021] A connecting element for connecting the flywheel accumulator can be engaged with the said crank wheel, ie the gear wheel acting as a transmission output element which drives the said crank.

[0022] In order to prevent the shock loads from the working unit or the intermittently pulsating power flow between the working unit and the flywheel accumulator from passing through the gear stages of the unit's transmission, a further development of the invention combines or branches off two separate drive trains on the transmission output side. On the one hand, the drive train that leads through the unit's transmission to the power source, for example, the PTO or the tractor's drive motor, is connected to the aforementioned transmission output element. On the other hand, the separate drive train that leads to the flywheel accumulator is connected to the aforementioned transmission output element.Since the additional second drive train for the flywheel accumulator is mounted on the transmission output of the aggregate transmission, the corresponding peak torques are not transmitted via the entire aggregate transmission, but branch off from the working unit on the transmission output side to the flywheel accumulator.

[0023] The two aforementioned first and second drive trains or their connecting elements can each be in end-to-end engagement with the transmission output element designed as a gear wheel, wherein the aforementioned connecting elements of the two drive trains can be arranged in different sectors, for example on opposite sides or in adjacent sectors, of the gear wheel. Depending on the design of the aggregate transmission, however, not both or even none of the connecting elements of the two drive trains need to be in end-to-end engagement with the gear wheel. For example, both drive trains could also each be engaged with the aforementioned gear wheel via a bevel gear, wherein if the two connecting elements are arranged in different sectors, the connecting elements could be arranged on the same side of the gear wheel.Conversely, it would also be possible to arrange such bevel gears on opposite sides of the common gear wheel serving as the transmission output element, in which case the connecting elements of the two drive trains could also be assigned to the same sector or section of the gear wheel.

[0024] Other engagement forms or mixed forms, such as a conical engagement on the one hand and a face engagement on the other, would be conceivable. However, the aforementioned design with both drive trains in face engagement is advantageous in terms of a compact design and a simple configuration of the gear wheel acting as the transmission output element. In particular, the two drive trains or their connecting elements can be in toothed engagement with the aforementioned gear wheel.

[0025] In an advantageous development of the invention, the two drive trains mentioned, which on the one hand lead to the flywheel storage unit and on the other hand lead through the unit transmission to the drive source, can each have at least one or more transmission stages, in particular several transmission and / or reduction stages for changing the speed.

[0026] In particular, the flywheel accumulator can be connected to the aforementioned transmission output element via at least one transmission gear stage, so that the flywheel accumulator runs at a higher speed than the aforementioned transmission output element.

[0027] For example, the aforementioned transmission gear stage can comprise a planetary gear, which can be single-stage or multi-stage. Such a transmission gear stage allows the flywheel accumulator to operate at a possibly significantly increased speed in order to achieve high kinetic energy for adequately smoothing the torque or load surges of the working unit.

[0028] In order to be able to accelerate the flywheel accumulator even with only limited torque from the drive source, especially to the intended high flywheel speeds, a further development of the invention can provide a starting aid for starting the flywheel accumulator. Such a starting aid can, in a further development of the invention, comprise a motor to assist starting, for example, a hydraulic motor or, in particular, an electric motor.

[0029] Such a starting auxiliary motor can advantageously be assigned directly to the drive train of the flywheel storage unit and / or be provided on the output side of the aggregate transmission, so that the drive torque of the starting motor does not have to be transmitted via the aggregate transmission in order to start the flywheel storage unit.

[0030] Preferably, said starting motor is connected to the gear stage by means of which the output speed of the aggregate transmission is translated into a higher flywheel speed. For example, the starting motor can be assigned to the aforementioned planetary gear, which can be provided in the second, separate drive train for the flywheel accumulator.

[0031] Depending on the design of the starting motor, a motor for relatively low torques and high speeds can be provided, whereby such a motor can be connected, for example, to the sun gear of the planetary gear or a sun gear shaft.

[0032] Alternatively, a starting motor with a relatively high torque and lower speeds can also be used. Such a motor can preferably be connected to the planetary carrier or the ring gear of the aforementioned planetary gear. Connection to an intermediate gear is also possible if this is advantageous for favorable space conditions or accessibility.

[0033] Preferably, the starting aid is designed such that the starting motor is only active or in operation when the flywheel accumulator is being started up. Advantageously, an overrunning clutch can be provided so that the starting motor can be switched off after the flywheel accumulator has been started up.

[0034] An overrunning clutch provided between the motor and the flywheel energy storage system transmits torque in one direction of rotation and rotates freely in the opposite direction of rotation, so that when the motor starts up, the motor can engage the flywheel energy storage system, while when the flywheel energy storage system is engaged, the motor can be switched off without being engaged by the flywheel energy storage system. Alternatively or in addition to a motor-driven starting aid, a switchable gearbox, for example a switchable planetary gear, can be provided as a starting aid. Using such a switchable starting gear, the flywheel energy storage system can be started up with an initially low gear ratio or, if necessary, with a reduction gear, and the gearbox can then be shifted up in one or more stages or even continuously in order to increase the gear ratio and achieve an increasingly higher flywheel energy storage speed with an inherently limited input speed.

[0035] In order to avoid damage to the drive train or the working unit when a blockage occurs during non-intended operation, for example when the working tool is blocked by stones or other obstacles, given the high kinetic energy of the flywheel storage device desired for intended operation, an advantageous development of the invention can provide a safety slip clutch which allows the flywheel storage device to slip relative to the working tool or the drive train leading thereto when a specified torque or load value in the drive train is reached or exceeded.Such a designated trigger value of the safety slip clutch can advantageously be dimensioned so large that, during normal operation, in which the fluctuating power consumption at the working unit occurs as intended, for example, the previously described load surges of a press, the safety slip clutch remains closed or does not slip, in order to smooth out the intended load fluctuations of the working unit. On the other hand, if unusual load surges occur, for example as a result of a drive train blockage, so that the torque or load in the drive train exceeds the trigger threshold of the safety slip clutch, the safety slip clutch slips and thus limits the torque occurring in the drive train or that can be transmitted to the safety slip clutch.

[0036] Such a safety slip clutch can advantageously be provided in the flywheel energy storage drive train in the immediate vicinity of the flywheel energy storage. If the flywheel energy storage drive train has a planetary gear as described above, the safety slip clutch can be provided, for example, on the sun gear or sun gear shaft, which transmits relatively smaller torques. Alternatively, the safety slip clutch can also be connected to the planet carrier or the ring gear of the planetary gear, which typically have lower speeds. For reasons of accessibility or limited space, for example, the safety clutch can also be provided on an intermediate gear, if present, in the flywheel energy storage drive train.

[0037] Advantageously, said safety slip clutch is provided in the flywheel accumulator drive train, in particular between the transmission output gear of the unit transmission and said flywheel accumulator.

[0038] The invention is explained in more detail below with reference to preferred embodiments and the accompanying drawings. In the drawings:

[0039] Fig. 1: a side view of a working machine with a drive train assembly according to an advantageous embodiment of the invention, wherein the working machine is designed as an agricultural baler, the working unit of which can be driven by the power take-off shaft of a tractor via a cardan shaft,

[0040] Fig. 2: a schematic representation of the drive train assembly of the working machine from Fig. 1 , showing the aggregate gearbox for driving the working tool of the working machine as well as the flywheel storage unit connected on the output side via a separate drive train, the flywheel storage unit being connected via a two-stage planetary gear,

[0041] Fig. 3: a schematic representation of the drive train of the working machine from Fig. 1 according to a further embodiment of the invention, according to which the flywheel accumulator connected to the output side of the aggregate transmission is connected via a single-stage planetary gear and an intermediate spur gear stage,

[0042] Fig. 4: a schematic representation of the drive train assembly of the working machine from Fig. 1 according to a further advantageous embodiment of the invention, according to which the flywheel accumulator connected to the output side of the aggregate transmission is connected via a planetary gear and an intermediate gear stage, wherein an auxiliary drive for starting up the flywheel accumulator is connected to the planetary gear via a spur gear stage,

[0043] Fig. 5: a side view of the aggregate transmission of the working machine from Fig. 1, showing the arrangement of the flywheel storage relative to the aggregate transmission,

[0044] Fig. 6: a schematic representation of the power flows during operation of the drive train assembly according to the embodiment of Fig. 3, wherein the power flow is shown at the highest torque peak, at which a high power flow occurs from the flywheel accumulator to the transmission output gear of the aggregate transmission and a low power flow from the drive source into the aggregate transmission,

[0045] Fig. 7: a representation of the power flows in the drive train assembly according to Fig. 3 during normal operation, in which energy is supplied from the drive source to the flywheel storage unit while simultaneously delivering power via the transmission output gear to the working unit, and

[0046] Fig. 8: A representation of the power flows of the drive train assembly according to Fig. 3 during the start-up process of the flywheel storage system, in which the flywheel storage system is started up by the starting motor and the drive train, which leads from the unit transmission to the power source, is rotated torque-free. As Fig. 1 shows, the work machine 1 can be designed as an agricultural machine for processing crops or possibly also for soil cultivation, in particular in the form of an attachment for attachment to a tractor 2.

[0047] The working machine 1 comprises at least one working unit 3, which may be subjected to cyclically highly fluctuating loads during operation and / or may exhibit cyclically highly fluctuating power consumption. As shown in Fig. 1, the working machine 1 can be designed in particular as a baler, the working unit 3 of which may comprise a tamper 4 that moves into a bale-forming chamber 5 or is cyclically moved back and forth therein in order to compress crop material picked up from the ground, which has been conveyed into the bale-forming chamber 5 via a suitable conveying device, into bales.

[0048] The working unit 3 is driven by a mechanical drive train assembly 12, which can comprise a cardan shaft 11, which can be connected in a rotationally fixed manner to the power take-off shaft of the tractor 2 and can be driven by the drive motor of the tractor 2, for example a diesel engine.

[0049] The said drive train assembly 12 comprises an aggregate transmission 6, which can be connected to the cardan shaft 11 and thus to the engine of the tractor 2 by means of a transmission input element 15, wherein the said transmission input element 15 can be an input shaft of the aggregate transmission 6.

[0050] The transmission output element 14 of the aggregate transmission 6, which forms the output side or the output element of said aggregate transmission 6, can be a crankshaft 7, which drives the tamper 4 of the working aggregate 3 back and forth via a connecting rod 8.

[0051] As Figures 2 to 4 show, the aforementioned aggregate transmission 6 can comprise one or more gear stages between its transmission input and output elements 15, 14, which can be designed as step-up or step-down stages. In particular, the aggregate transmission 6 can comprise a bevel gear stage 24, which can drive the transmission output element 14, in particular the aforementioned coupling shaft 7, directly or via an intermediate stage 25. The intermediate stage 25 can, for example, be a spur gear stage, see Figures 2, 3, and 4.

[0052] In particular, the transmission output element 14 can have a gear 26, preferably a spur gear, which can in particular be designed as a spur-toothed pinion, wherein said gear 26 can be seated on the crankshaft 7 and connected thereto in a rotationally fixed manner. Said gear 26 can be driven by the aforementioned intermediate stage 25 from the drive source 10, i.e., the drive train 9 connected to the power take-off shaft of the tractor 2 drives the output-side gear 26 with the drive power of the tractor 2 or its power take-off shaft via the cardan shaft 11 and the aggregate transmission 6, which drives the crankshaft 7 rotationally and thus drives the tamper 4 back and forth.

[0053] As Figures 2, 3 and 4 further show, a flywheel accumulator 13 is connected to the output side of the aggregate transmission 6 via a second drive train 17, wherein the second drive train 17 driving the flywheel accumulator 13 or conversely driven thereby can be connected in particular to the transmission output element 14 of the aggregate transmission 6 in the form of the gear wheel 26, so that the kinetic energy coming from the flywheel accumulator 13 can be passed directly to the crankshaft gear wheel 26 to smooth out load shocks of the tamper 4.

[0054] As Figures 2 to 4 show, the second drive train 17 can be connected to the crankshaft gear wheel 26 of the aggregate transmission 6 via a spur gear stage 27.

[0055] The spur gears 29 and 28 of the spur gear stages 25 and 27, via which the aforementioned first and second drive trains 9 and 17 are connected to the output-side crankshaft gear 26, can mesh with the aforementioned gear 26 in various circumferential sections, for example, arranged on opposite sides of the gear 26 or in adjacent sectors of the gear 26, see Figure 5, whereby an overall compact design of the aggregate transmission 6 can be achieved. For example, the two aforementioned spur gears 28, 29 can both mesh with a lower circumferential half of the crankshaft gear 26, so that the aggregate transmission 6 and the flywheel accumulator 13 can be arranged entirely below the crankshaft 7, see Figure 5, resulting in an overall compact and cost-effective design.

[0056] The flywheel accumulator 13 can be connected to the crankshaft gear wheel 26 via one or more further gear stages or the said second drive train 17 can have one or more gear stages, in particular in order to translate the speed of the crankshaft 7 into a higher flywheel accumulator speed.

[0057] As Figure 2 shows, the second drive train 17 can, for example, have a two-stage or multi-stage planetary gear 18, wherein the flywheel accumulator 13 can, for example, be connected to the sun gear 30 of the second planetary gear stage 18b.

[0058] On the input side, the planetary gear 18, for example the planet carrier 31 of the first planetary stage 18a, can be connected to the aforementioned crankshaft gear wheel 26 via an intermediate stage, for example a spur gear stage 32, see Figure 2.

[0059] In order to be able to start up the flywheel accumulator 13, which runs at high speeds during operation, even if the drive source 10 can only provide a limited starting torque, a starting aid 19 can be provided for starting the flywheel accumulator 13, wherein the said starting aid 19 can have a starting motor 20, for example an electric motor, wherein the said starting motor 20 can be connected, for example, to the sun gear 30 of the second gear stage or can be engaged therewith in order to be able to drive the sun gear shaft and thus the flywheel accumulator 13.In order to be able to switch off the starting motor 20 during the intended operation of the drive train assembly 12, the starting motor 20 can be connected to the flywheel accumulator 13 via an overrunning clutch 21, which drives the flywheel accumulator 13, in particular the sun gear 30, during starting, but on the other hand allows the starting motor 20, for example the sun gear 30, to rotate faster than the starting motor 20 or can rotate even when the starting motor 20 is stationary.

[0060] In order to avoid an overload in the drive train assembly 12 in the event of a blockage of the working unit 3, for example due to a stone on the tamper 4 or a blockage of another section of the drive train assembly 12, for example in the area of ​​the planetary gear 18 and / or the intermediate stage 27 or 32, a safety slip clutch 33 is preferably provided, which can preferably be arranged directly on the flywheel accumulator 13 or can separate all gear stages of the second drive train 17 from the flywheel accumulator 13. The said safety slip clutch 33 forms, so to speak, an emergency slip clutch, which does not open or uncouple the flywheel accumulator 3 when the intended load fluctuations or torque surges of the working unit 3 occur, but only when a torque surge occurs which is higher than or significantly higher than the intended load or torque surges.Torque shocks that occur during normal operation of the working unit 3.

[0061] As Figure 2 shows, the mentioned safety slip clutch 33 can be provided, for example, between the flywheel accumulator 13 and the shaft of the sun gear 30 or can be in engagement with the flywheel accumulator 13 on the one hand and the sun gear 30 on the other hand.

[0062] As Figure 3 shows, the second drive train 17 can also have gear stages—designed differently compared to Figure 2—for example, a single-stage planetary gear 18 and an additional intermediate stage between the planetary gear 18 and the connection to the crankshaft gear wheel 26, for example in the form of an additional spur gear stage 34, see Figure 3. Independently of this, the starting motor 20 can also be connected to the sun gear of the planetary gear 18 in the embodiment according to Figure 3. Again independently of this, the flywheel accumulator 13 can also be connected to the sun gear 30 in order to rotate at its speed, whereby here too a safety slip clutch 33 can be provided between the flywheel accumulator 13 and the gear stages of the second drive train 17, in particular between the flywheel accumulator 13 and the shaft of the sun gear 30, see Figure 3.

[0063] Figure 4 shows a further example of the second drive train 17. Here too, the second drive train 17, similar to the embodiment according to Figure 3, comprises a single-stage planetary gear 18 and an intermediate stage, in particular in the form of a spur gear stage 34, between the planetary gear 18 and the connection to the crankshaft gear wheel 26. As Figure 4 shows, the flywheel accumulator 13 can be connected to the sun gear 30 of the planetary gear 18 and engage with the shaft of the sun gear 30 via a safety slip clutch 33.

[0064] The start-up motor 20, which is also provided, can be connected via an intermediate gear stage 35, for example in the form of a spur gear stage, whereby an overrunning clutch 21 can also be provided here. As Figure 4 shows, the start-up motor 20 can be connected to the planet carrier 31 of the planetary gear 18 via the aforementioned intermediate stage 35 in order to drive the aforementioned planet carrier 31 and thus be able to start the flywheel accumulator 13.

[0065] Figures 6 to 8 show the power flows occurring in various operating situations, with the hatched arrows representing the individual power flows or their branches. A thick arrow width or hatched area symbolizes a comparatively high transmitted power, while narrow arrows or narrow hatched areas symbolize relatively small power flows.

[0066] Figure 6 shows the power flows during normal operation of the working unit 3 when a load surge from the tamper 4 is smoothed out by the flywheel accumulator 13, i.e. a relatively high power flow is sent from the flywheel accumulator 13 to the transmission output element 14, i.e. the crankshaft gear wheel 26, in order to smooth out the load peak occurring at the tamper 4. As Figure 6 further illustrates, the power flow coming from the tractor 2 via the first drive train 9 remains normal or relatively small compared to the power flow from the flywheel accumulator 13, i.e. the load peak occurring at the tamper 4 is not introduced into the first drive train 9.

[0067] As Figure 6 shows, the power flows from the flywheel accumulator 13 and from the drive source 10 are summed at the crankshaft gear wheel 26.

[0068] Figure 7 also shows the power flows during normal operation of the working unit 3, showing an operating phase in which power is supplied only from the drive source 10. The power supplied from the drive source 10 via the unit transmission 6 drives the crankshaft 7 on the one hand and also drives the flywheel accumulator 13 via the second drive train 17. The power flow coming from the drive source 10 is split, so to speak, at the crankshaft gear 26.

[0069] Finally, Figure 8 shows the power flows during the starting process or the starting or ramping up of the flywheel accumulator 13, whereby the starting motor 20 feeds power into the planetary gear 18 and thereby ramps up the flywheel accumulator 13. The first drive train 9, and thus the aggregate transmission 6 and the propeller shaft 11, are also dragged along, so to speak, without load, via the common crankshaft gear 26.

[0070] • The PTO shaft can o enable the bevel gear set and the intermediate pinion to be dimensioned smaller than before, because no power and no peak torque from the flywheel need to be transmitted anymore; o enable cost-efficient production, because the bevel gear set is a machine element in the baler gearbox that greatly influences the value and can be dimensioned smaller. • The flywheel shaft can o be connected to the teeth of the crankshaft gear via another pinion o transmit the power from the flywheel shaft via a second tooth mesh from the crankshaft gear, to which the power from the PTO shaft is also supplied, whereby the power division allows the crankshaft gear teeth to be dimensioned smaller; o bring the flywheel to higher speeds through a gear ratio in the flywheel shaft and thus store a high level of kinetic energy; o reduce the weight of the flywheel (Ero t = x Jo xw 2 ); o enable the start-up of the flywheel and the baler via an auxiliary drive on the flywheel line in an advantageous manner with power division and bypassing the PTO line; o avoid unnecessary slip (overtaking of the freewheel) when the synchronous speed is reached between the PTO speed and the flywheel speed, whereby the speeds can optionally be monitored up to the synchronization point; o bring the flywheel and the baler up to speed via a large slip clutch on the drive; o make the safety slip clutch of the flywheel on the high-speed shaft smaller; o enable power division via the flywheel.

[0071] • The intermediate wheel can o provide more structural freedom for arranging the flywheel so that the crank arms do not collide; o have a double wheel for gear ratio adjustment (see Figures 3, 4, 6, 7, 8) and thus coordination for optimal rotational energy without, for example, changing the flywheel; o show a swelling tooth load due to a double wheel, thus higher torques can be transmitted in contrast to a changing tooth load, o can be arranged in the direction of travel, depending on the space available (currently transverse to the direction of travel); o by using helical gears on the intermediate wheel, a flywheel axis can also be perpendicular, i.e. transverse, to the direction of travel or in any direction.

[0072] • The safety slip clutch can o be dimensioned so that in the event of a blockage in the drive train or in the baler channel, the moment of inertia is limited to a fixed value; o be advantageously arranged in the flywheel train, in the immediate vicinity of the flywheel, e.g. on the sun gear shaft, since this gear carries small torques; o alternatively be arranged on the web or ring gear of the planetary gear, since these have lower speeds; o for other reasons, such as accessibility to the clutch or confined space, also be arranged on the intermediate gear.

[0073] • The auxiliary drive can have / be designed as follows: o The drive can be hydraulic or electric. o The drive can be coupled to the sun gear shaft for low torques and high speeds. o Alternatively, the drive can be placed on the web or the ring gear for high torques and low speeds. A connection to the intermediate gear is also possible if this is necessary for technical reasons, such as favorable space conditions or advantageous accessibility. o The auxiliary drive is only used to start up the flywheel. This is equipped with an overrunning clutch so that it can be switched off after the start-up process. o Alternatively, the auxiliary drive can be disengaged from the tooth mesh with the pinion in a similar way to the “starter principle” in a vehicle, so that the pinion can be disengaged from the tooth mesh of the mating gear and does not have to run idle (torque-free).

[0074] The planetary gear can be o single-stage with improved oil flow, if necessary with a shift of transmission components to the intermediate gear; have a short axial design; o two-stage, if necessary with the use of a common ring gear; o fully integrated into the housing of the baler drive and very short in construction, so that the crank arms do not collide; o partially integrated; o flanged on the outside; o arranged around the crankshaft gear, in particular

[0075] ■ optimized for oil management, low splash losses

[0076] ■ designed for optimal bearing load on the crankshaft,

[0077] ■ be configured for a modular system, adapted to different tractor powers and multiple arrangements;

[0078] ■ have a multiple arrangement for switching on operations.

[0079] • The flywheel / flywheel housing can be o external for good accessibility, o encapsulated for less air turbulence, o encapsulated and under vacuum, whereby vacuum can be provided to reduce ventilation losses.

Claims

Claims 1. Drive train assembly for driving a working unit (3) with fluctuating power consumption from a drive source (10), with a unit gearbox (6) which 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) by a gearbox output element (14) and to the drive source (10) by a gearbox input element (15), and with a flywheel accumulator (13) for mitigating load surges and / or power consumption fluctuations, characterized in that the flywheel accumulator (13) is connected on the output side of the unit gearbox (6) to the drive train which goes from the unit gearbox (6) to the working unit (3).

2. Drive train assembly according to the preceding claim, wherein the flywheel accumulator (13) is connected to said transmission output element (14), to which the working unit (3) is simultaneously connected.

3. Drive train 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 crank (7) leading to the working unit (3) and, on the other hand, is in engagement with a connecting element (16) for connecting the flywheel accumulator (13).

4. Drive train assembly according to one of the preceding claims, wherein two separate drive trains are brought together at said transmission output element (14), wherein a first drive train (9) leads from said transmission output element (14) through the aggregate transmission (6) and across its gear stages to the drive source (10) and a second drive train (17) leads from said transmission output element (14) past the gear stages of the aggregate transmission (6) to the flywheel accumulator (13).

5. Drive train assembly according to the preceding claim, wherein said first and second drive trains (9, 17) are each in end engagement with the transmission output element (14) designed as a gear wheel and extend from the transmission output element (14) in different sectors, in particular on opposite sides.

6. Drive train assembly according to one of the two preceding claims, wherein the first and second drive trains (9, 17) each have at least one or more transmission ratio reduction gear stages.

7. Drive train assembly according to one of the preceding claims, wherein the flywheel accumulator (13) is connected to the transmission output element (14) via at least one transmission gear stage, so that the flywheel accumulator (13) runs at a higher speed than said transmission output element (14).

8. Drive train assembly according to the preceding claim, wherein the transmission gear stage comprises a planetary gear (18).

9. Drive train assembly according to one of the preceding claims, wherein a starting aid is provided for starting the flywheel accumulator (13).

10. Drive train assembly according to the preceding claim, wherein the starting aid (19) has a motor (20) for assisting the starting of the flywheel accumulator (13), in particular a hydraulic motor or an electric motor.

11. Drive train assembly according to the preceding claim, wherein an overrunning freewheel (21) is provided between the motor (20) and the flywheel accumulator (13), which overrunning freewheel permits relative rotation between the flywheel accumulator (13) and the motor (20) in one direction of rotation and blocks it in an opposite direction of rotation, so that when the flywheel accumulator (13) is rotating as intended, the motor (20) can be switched off.

12. Drive train assembly according to one of the preceding claims, wherein a switchable transmission, in particular a switchable planetary gear (18), is provided as the starting aid (19) to assist the starting of the flywheel accumulator (13).

13. Drive train assembly according to one of the preceding claims, wherein the aggregate transmission (6) has at least one spur gear stage (22) and at least one intermediate gear stage (23) between its transmission input element (15) and its transmission output element (14).

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

15. 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).

16. 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.

17. Work machine according to one of claims 14 to 16, which is designed as an attachment for attachment to 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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