TRANSMISSION SYSTEM

Description

[0001] The present invention relates to a transmission system for an agricultural machine. DE102015114559A1 discloses a transmission system with a power-split transmission section and a manual transmission, wherein the power-split transmission section has at least one variable transmission branch and one mechanical transmission branch.

[0002] A transmission system typically consists of an input shaft, a shiftable gearbox, and an output shaft. Transmission systems convert the input power into torque and speed and transmit this to the output.

[0003] A transmission system can utilize either manual or continuously variable transmissions as components. Manual transmissions are implemented using powershift clutches that connect different meshed gear stages. This shifting point, also known as the powershift point, leads to a change in the speed of the meshed transmission system components, resulting in noise, wear, and an interrupted power flow.

[0004] The transmission system can alternatively be implemented as a continuously variable transmission. This is achieved using hydraulic variators to reliably convert higher drive power. Part of the drive power is converted into hydraulic power on the input side of the continuously variable transmission using hydrostats. The proportion of hydraulic power can be varied using the variators. On the output side, the hydraulic energy is converted back into mechanical energy. Continuously variable transmissions usually have an output shaft to simplify their design. This requires a speed change on the variator output shaft at the time of shifting of the transmission system, simultaneously with the gear change in the downstream transmission. This process takes time, which slows down the shifting process and leads to inertia in the transmission system.

[0005] As an option, the transmission system can be equipped with a continuously variable transmission with two variator output shafts. This eliminates the need for simultaneous speed changes during gear shifting. This type of design results in increased complexity due to the second variator output and the larger number of components. Overall, such transmission systems require more maintenance, along with increased wear and increased noise.

[0006] The present invention provides a transmission system that overcomes the problems mentioned.

[0007] The transmission system according to the invention is suitable for operation with a drive machine and comprises an input shaft for the drive line, at least one output shaft for delivery to a drive, a power-split transmission section, a manual transmission, a transmission system control, wherein the power-split transmission section has at least one variable transmission branch and a mechanical transmission branch, and the variable branch has at least one electric machine on the input and output sides for generator and motor operation, which are electrically connected to one another, wherein the drive power is divided and directed by the mechanical and variable branches, and with an input-coupled magnetic-electric epicyclic gear stage which combines the variable branch and mechanical branch, with an inner rotor, an outer stator and a modulating ring,and the magnetic-electric epicyclic gear stage can be controlled by the second electric machine in such a way that the output shaft of the transmission system rotates counter to the direction of rotation on an input shaft, whereby a forward and reverse operation of the transmission system can be carried out.

[0008] In the transmission system according to the invention and the use of electric motors in the variable branch together with a magnetic-electric epicyclic gear stage, the excitation frequency in the stator windings of the magnetic-electric epicyclic gear stage is switched simultaneously at the transmission shift point. This switching causes a change in the speed of an intermediate shaft. However, only a low torque is required, enabling a faster shifting process of the transmission system compared to the prior art. The shifting processes thus reduce the coordination effort required by the operator and shorten the duration of the shifting process. The vehicle is exposed to fewer speed fluctuations, ensuring increased driving comfort.

[0009] In a further embodiment, the magnetic-electric epicyclic gear stage is controlled by the second electric machine in such a way that an output shaft of the magnetic-electric epicyclic gear stage rotates in the opposite direction to the input shaft of the transmission system.

[0010] The control of the magnetic-electric epicyclic gear stage enables the speed and direction of the input shaft to be superimposed on an output of the magnetic-electric epicyclic gear stage, so that the resulting output speed and direction of rotation of the output shaft are set opposite to the input shaft. An additional reverse gear can be eliminated and the entire design of the transmission system is simplified, reducing the number of required parts and the associated manufacturing and installation processes.

[0011] In a further embodiment, an additional module for reversing the direction of rotation is provided between the first electric machine and the magnetic-electric epicyclic gear stage in the power flow.

[0012] The reversing module can be designed separately from the gearbox, reducing complexity. The module can be designed for lower torque, reducing production costs and part weight.

[0013] In a further development, one gear of the manual transmission is an additional reverse gear.

[0014] Integrating the reverse gear into the manual transmission ensures compatibility with conventional manual transmissions. The required installation space for the power-split transmission section is reduced.

[0015] In one embodiment, an additional module for reversing the direction of rotation is provided between the magnetic-electric epicyclic gear stage and the manual transmission in the power flow.

[0016] The separate arrangement facilitates accessibility of the module for maintenance purposes.

[0017] In a further development, an additional module for serial electrical starting in the power flow is planned.

[0018] The module enables the vehicle to start using the electrical power branch, which corresponds to the power flow through the two electric motors, while simultaneously shutting off the mechanical power branch. Purely electric starting allows high torque to be transferred to the output. This is particularly advantageous when starting with a high vehicle torque, as high tractive forces must be applied at low speeds. The module ensures this.

[0019] In one version, the module is provided for serial electrical starting between the input shaft of the transmission system and the magnetic-electric epicyclic gear stage in the power flow.

[0020] The module mechanically decouples the primary drive from the vehicle's output. The drive power is converted into electrical power and transferred to the output. By placing it upstream of the magnetic-electric epicyclic gear stage in the power flow, the module can be installed within the power-split transmission section. The electric motors can be used for conversion and output.

[0021] In one design, the module is intended for serial electrical starting in the power flow between the first electric machine and the magnetic-electric epicyclic gear stage.

[0022] By placing it upstream of the magnetic-electric epicyclic gear stage in the power flow, the module can be positioned within the power-split transmission section. The electric motors can be used here for conversion and output.

[0023] In a further development, the module for serial electrical starting is provided in the power flow between the module for reversing the direction of rotation and the magnetic-electric epicyclic gear stage.

[0024] The invention is further described with reference to the following figures. Fig. 1 a structure of the transmission system according to the invention; Fig. 2 a state-of-the-art structure; Fig. 3 a further structure of the transmission system according to the invention; Fig. 4 a further schematic structure of the transmission system; Fig. 5 a further schematic structure of the transmission system; Fig. 6a further schematic structure of the transmission system; Fig. 7 a further schematic structure of the transmission system; Fig. 8 a further schematic structure of the transmission system; Fig. 9 a further schematic structure of the transmission system; Fig. 10 a further schematic structure of the transmission system; Fig. 11 a further schematic structure of the transmission system; Fig. 12 another schematic structure of the transmission system.

[0025] In Figure 1A design of the transmission system 10 is shown. Drive power is transmitted from a drive, usually an internal combustion engine, to an input shaft 12. However, the drive motor can also be a hydraulic motor. A rotor of the input-side electric motor and the inner rotor 52 of the magnetic-electric epicyclic gear stage 50 are non-rotatably connected to the input shaft 12. The input shaft simultaneously supplies drive power to a power take-off or PTO and is designed as a continuous shaft.

[0026] The input-side electric machine 16 is electrically connected to the output-side electric machine 18 and to a transmission system control 40. The output-side electric machine 18 is operatively connected to the modulating ring 56 of the magnetic-electric epicyclic gear stage 50, which in turn interacts with the inner rotor 52. The input-side and output-side electric machines, together with the magnetic-electric epicyclic gear stage, constitute the variable transmission branch 24, and together with the input shaft, the power-split transmission section 20. The mechanical transmission branch 24 is formed from the continuous input shaft 12.

[0027] The modulating ring 56 is connected to the power flow by means of a hollow shaft which surrounds the input shaft 12. The hollow shaft is designed to be connected to the manual transmission 30 and, by means of a powershift clutch, to a first gear pair F1 or a further gear pair F2. The gear pairs F1 and F2 form the manual transmission 30 of the transmission system 10. The gear pairs F1 and F2 transmit the drive power to the output shaft 14, which in turn serves to transmit it to the output. The second gear pair F2 is not rotationally fixed to the output shaft 14, but is rotationally fixed to it via a coupling element when shifting. The first gear pair F1 is rotationally fixed to the output shaft 14, so that when the coupling element is freewheeling and when the powershift clutch in the manual transmission is in the corresponding position, the drive torque is transmitted via the first gear pair F1.

[0028] Another gear pair R for a reverse gear can be connected to the second gear pair F2. The direction of rotation is reversed by means of an additional intermediate shaft between the input shaft 12 and the output shaft 14. On the output shaft, the gear pair R is not rotationally fixedly connected to the output shaft 14 and is engaged by means of the coupling element. Thus, depending on the position of the coupling element and the powershift clutch, the first gear pair F1, the second gear pair F2, or the reverse gear R is connected to the output.

[0029] The drive power is split in the power-split transmission section 20 by controlling the input-side electric motor 16, and a corresponding portion is converted into electrical power. The remaining mechanical portion is routed through the input shaft 12 or remains in it. The electrical power is controlled by the transmission system control 40, and the output-side electric motor 18 is controlled and supplied with electrical power. By controlling the current and voltage, the generated torque and speed are influenced, so that, with the action of the modulating ring 56 and the inner rotor 52, an outgoing speed and an outgoing torque are established at the modulating ring 56.

[0030] The portion of remaining power in the input shaft is sent to the PTO, while the remaining portion is sent to the manual transmission.

[0031] At a shifting point, when triggered by the transmission system control, one of the powershift clutches for F1 or F2 is engaged, while the other powershift clutch is disengaged. At the same time, the coupling element on output shaft 14 is switched. Without the invention, the transmission system would experience a change in the moment of inertia due to the change in the power path and the resulting speed and torque, so that this change would be noticeable to the operator. At the same time, the vehicle experiences a change in speed.

[0032] To prevent this, the invention provides that, simultaneously with the shifting operations in the manual transmission 30, an adjustment of the electric drive power takes place such that the transmission system control 40 changes the excitation frequency of the windings in the outer stator 54 of the magnetic-electric epicyclic gear stage 54. This change itself does not cause any torque or speed change, so that the change in the moment of inertia of the transmission system is kept very small. Due to this reduction, the vehicle does not experience any perceptible change in speed.

[0033] The input torque is applied via the input shaft 12 simultaneously to the first electric machine 16 and the inner rotor 52. The first electric machine 16 converts this into electrical power, with the control being carried out by the transmission system control 40. The electrical power is output via the second electric machine 18 with an outer stator 54. By changing the excitation frequency, different speeds can be set in the magnetic-electric epicyclic gear stage. The power applied to the inner rotor 52, as well as the power applied to the outer stator 54, determines the power applied to the modulating ring 56. The power is output to the manual transmission 30 via the modulating ring 56 and transmitted via the gear pairs F1, F2 or R by engaging the respective clutches.

[0034] Overall, the transmission system is capable of compensating for the pulse occurring at the switching time and a simultaneous change in the speed in the magnetic-electric epicyclic gear stage 50 and of maintaining harmonious, jerk-free operation during switching operations.

[0035] The transmission system 10 can simultaneously enable purely electric starting, as there is no mechanical connection between the drive and output. By maintaining battery storage and feeding additional electrical energy into the second electric motor 18, purely electric starting can be achieved. This is done in the serial electric starting module 70. This is particularly advantageous with a high trailer load, which normally requires a high reduction ratio for starting at low speeds.

[0036] Figure 2describes a known power-split transmission system from the state of the art, which has a variable branch with two outputs 1 and 2.

[0037] The drive power is transmitted via the input shaft 112 to a first gear G1 and by means of the further gears G2 and G zw or G3 respectively to a first electric machine 116 and to a reverse gear 132.

[0038] The variable power component is electrically transmitted to a second electric machine 118 and recombined with the mechanical power by means of a magnetic electric epicyclic gear stage 150. In contrast to the present invention, the prior art transmission system has two outputs OUT1 and OUT2, which, depending on the application, can be connected to the output via a powershift clutch. The drive power is then routed through a manual transmission 130, with different gear ratios being determined by two clutches.

[0039] The solution using two outputs after the power-split transmission enables the outputs to be switched simultaneously with the switching of the powershift clutches in the manual transmission 130. This changes the speed and torque at the output of the power-split transmission section 120 along with the change in speed and torque in the manual transmission 130. This results in a balancing of the impulse at the time of switching. In contrast to the present invention, the structure of the transmission system 100 is significantly more complex. Two outputs of the power-split transmission section must be provided, along with two powershift clutches and two additional planetary gear stages. In parallel, the control of the transmission system 130 is designed so that switching is only possible between two different speed ratios. Overall, this leads to greater manufacturing complexity, a higher number of components, and increased weight.

[0040] Figure 3shows a further embodiment of the transmission system according to the invention. The first electric motor 16 is driven via a shaft of a gearwheel, which is supplied with the input torque at a constant ratio. The input shaft 12 transmits the drive power to the planetary carrier of an epicyclic gear. This has a lockable outer ring and a powershift clutch with which the planetary carrier can be coupled to the sun gear. The output of the planetary gear is also via the sun gear, so that the drive power continues to be transmitted in parallel via the input shaft 12 and the sun gear shaft.Further down the power path, the variable power component is introduced by means of the second electric machine 18 and another sun gear of the magnetic-electric epicyclic gear stage 50, whereby the modulatable ring 56 can be coupled to the inner rotor in its function as a sun gear by means of another powershift clutch. The variable power component is controlled between the first and second electric machines 16 and 18. A subsequent manual transmission 30 with another parallel shaft to the output follows. The manual transmission has two gear pairs F1 and F2 which can be coupled to the sun shaft by means of powershift clutches. The input shaft 12 supplies the power take-off shaft or PTO. In addition, another reduced gear is provided as a low-speed gear or creep gear.

[0041] The reverse gear in the transmission system 10 is provided by closing or opening the powershift clutch C Fwd, which reverses the direction of rotation on the sun gear or sun shaft of the planetary gear.

[0042] Figures 4 to 12 show a schematic structure of further embodiments of the transmission system 10 according to the invention. The individual components correspond in design to those of the Figure 1 and 3 .

[0043] Figure 4 shows a transmission system 10 according to the invention Figure 1, whereby this design does not have a separate reverse gear. The drive torque is split between the mechanical transmission branch 24 and the variable transmission branch 22, which consists of the first and second electric motors 16 and 18. The second electric motor 18 is part of the magnetic-electric epicyclic gear stage 50. Following in the power path is the manual transmission 30. From there, the drive power is directed to one or more axles of the vehicle and finally to the output.

[0044] Figure 5 shows an embodiment wherein the transmission system 10 additionally has a reverse gear 32, which is provided in the power path between the manual transmission 30 and the vehicle axles.

[0045] Figure 6shows a design in which the reverse gear 32 is formed in the area between the first electric motor 16 and the magnetic-electric epicyclic gear stage 50 in the power path. Additionally, a module for serial electric starting 70 is provided in the power path, which enables the vehicle to start without direct mechanical coupling of the drive to the output.

[0046] Figure 7 describes an embodiment in which the reverse gear 32 is formed in the power path between the magnetic-electric epicyclic gear stage 50 and the manual transmission 30.

[0047] Figure 8 shows an embodiment in which the module for serial electric starting 70 is provided in the power path between the first electric motor 16 and the magnetic-electric epicyclic gear stage 50. Furthermore, the reverse gear 32 is formed between the manual transmission 30 and the vehicle axles.

[0048] Figure 9describes a version with the module for serial electrical start-up 70 according to Figure 8 , whereby a reverse gear has been omitted. This is carried out via the magnetic-electric epicyclic gear stage 50, so that a reversal of the direction of rotation is present at the output of the magnetic-electric epicyclic gear stage 50.

[0049] Figure 10 shows a further embodiment, wherein the module for serial electric starting 70 is formed in the power path between the first electric machine 16 and the magnetic-electric epicyclic gear stage 50. The reverse gear 32 is provided in the power path between the magnetic-electric epicyclic gear stage 50 and the manual transmission 30.

[0050] Figure 11 shows an embodiment in which the reverse gear 32 is formed within the manual transmission 30.

[0051] Figure 12shows an embodiment with the reverse gear 32 in the power path between the first electric machine 16 and the magnetic-electric epicyclic gear stage 50.

Claims

1. Transmission system (10) suitable for operation with a drive machine, having an input shaft (12) for the drive power, at least one output shaft (14) for outputting same to a drive, a power-split transmission section (20), a manual transmission (30), a transmission system controller (40), wherein the power-split transmission section (20) has at least one variable transmission branch (22) and a mechanical transmission branch (24), and the variable transmission branch (22) has, on the input and output sides, in each case at least one first and second electric machine (16, 18) for the generator and motor operation, which electric machines are electrically connected to one another, wherein the drive power is divided up and conducted by the mechanical and variable transmission branch (22, 24), and to an input-coupled, magnetically electric epicyclic gear stage (50) which brings together the variable transmission branch (22) and mechanical transmission branch (24), to an inner rotor (52), an outer stator (54) and a modulating ring (56), characterized in that the magnetically electric epicyclic gear stage (50) can be activated by the second electric machine (18) in such a manner that the output shaft (14) of the transmission system (10) rotates counter to the direction of rotation at an input shaft (12), as a result of which a forward and reverse operation of the transmission system (10) can be carried out.

2. Transmission system (10) according to Claim 1, characterized in that the magnetically electric epicyclic gear stage (50) is activated by the second electric machine (18) in such a manner that an output shaft of the magnetically electric epicyclic gear stage (50) rotates in the opposite direction to the input shaft (12) of the transmission system (10).

3. Transmission system (10) according to Claim 1, characterized in that an additional module for reversal of the direction of rotation (60) is provided in the power flux between the first electric machine (16) and the magnetically electric epicyclic gear stage (50).

4. Transmission system (10) according to Claim 1, characterized in that one speed of the manual transmission (30) is an additional reverse gear (32).

5. Transmission system (10) according to Claim 1, characterized in that an additional module for reversal of the direction of rotation (60) is provided in the power flux between the magnetically electric epicyclic gear stage (50) and the manual transmission (30).

6. Transmission system (10) according to one of the preceding claims, wherein a further additional module for serially electric starting (70) is provided in the power flux.

7. Transmission system (10) according to Claim 6, characterized in that the further additional module for serially electric starting (70) is provided in the power flux between the input shaft (12) of the transmission system (10) and the magnetically electric epicyclic gear stage (50).

8. Transmission system (10) according to either of Claims 6 and 7, characterized in that the further additional module for serially electric starting (70) is provided in the power flux between the first electric machine (16) and the magnetically electric epicyclic gear stage (50).

9. Transmission system (10) according to Claim 3, characterized in that the module for serially electric starting (70) is provided in the power flux between the module for reversal of the direction of rotation (60) and the magnetically electric epicyclic gear stage (50).