Powershift group transmission for a work machine and agricultural vehicle

Abstract

The invention relates to a powershift group transmission (100) for a work machine, comprising a splitter transmission (110) in countershaft design and a powershift transmission (120) in countershaft design connected downstream of the splitter transmission (110), wherein the powershift transmission (120) comprises a first shaft (131), a second shaft (132), a third shaft (133) and a fourth shaft (134), a first gear pair (141) and a second gear pair (142), a first powershift clutch (151) and a second powershift clutch (152) and comprises a first shifting element (154), a second shifting element (155) and a third shifting element (156), and wherein the splitter transmission (110) has a first output (111) via which the first shaft (131) of the powershift transmission (120) can be driven directly.The group transmission (100) according to the invention is characterized in that the splitter transmission (110) further comprises a second output (112), via which the second shaft (132) of the powershift transmission (120) can be directly driven. The invention further relates to a corresponding agricultural utility vehicle.

Description

[0001] The present invention relates to a powershift group transmission for a work machine according to the preamble of claim 1 and a corresponding agricultural utility vehicle.

[0002] It is known in the prior art that agricultural commercial vehicles, particularly agricultural tractors, must be able to provide a wide range of finely graduated driving ranges due to the broad spectrum of tasks they perform. This generally requires, among other things, a comparatively large spread between a lowest and a highest gear. Furthermore, small geometric step changes must be implemented between the individual gears so that, in combination with the large spread, the required high number of gears can be achieved. In order to be able to provide this large number of gears at a reasonable cost, transmissions for agricultural or municipal commercial vehicles are often designed as a group construction. One of these transmission groups can, for example, be designed as a powershift transmission.

[0003] In general, it is desirable to design the individual gear groups of a group transmission in a compact, weight-saving and cost-effective manner while at the same time being highly efficient.

[0004] In this context, EP 2 916 044 A1 discloses a motor vehicle transmission designed as a group, which is intended for use in an agricultural utility vehicle, for example, a farm tractor. The motor vehicle transmission is composed of several transmission groups, one of which is implemented in the manner of a dual-clutch transmission.

[0005] From DE 10 2021 208 975 A1, a powershift transmission of a motor vehicle with a splitter group having several powershift stages, a powershiftable intermediate group and a synchronous transmission group is known.

[0006] DE 10 2011 076 391 A1 describes a parallel transmission comprising a splitter group and a range group, each of which is divided into two parallel transmission branches. Each of the transmission branches can be selected by actuating a corresponding powershift element.

[0007] However, the known powershift group transmissions are disadvantageous in that they have a comparatively large number of components and in particular gears, which makes them heavy and expensive and requires a large amount of installation space.

[0008] It is an object of the invention to propose an improved powershift group transmission for a work machine.

[0009] This object is achieved according to the invention by the powershift group transmission for a work machine according to claim 1. Advantageous embodiments and further developments of the invention emerge from the dependent claims.

[0010] The invention relates to a powershift group transmission for a work machine, comprising a splitter transmission in countershaft design and a powershift transmission in countershaft design connected downstream of the splitter transmission, wherein the powershift transmission comprises a first shaft, a second shaft, a third shaft and a fourth shaft, a first pair of gears and a second pair of gears, a first powershift clutch and a second powershift clutch and a first shifting element, a second shifting element and a third shifting element and wherein the splitter transmission has a first output via which the first shaft of the powershift transmission can be driven directly.

[0011] Thus, a group transmission is provided, i.e., a complete transmission consisting of several independently shiftable individual transmissions. The group transmission according to the invention comprises at least one splitter transmission and one powershift transmission, both of which are designed as countershafts. In addition, further transmission groups, such as a range transmission or a reversing transmission, can also be provided.

[0012] The group transmission is driven by a drive unit, which can be embodied, for example, as an internal combustion engine or an electric motor. Since the splitter transmission is connected upstream of the powershift transmission, a drive path from the drive unit first runs through the splitter transmission before passing through the powershift transmission. Additional transmission groups or drivetrain elements can be arranged upstream or downstream of the splitter transmission or the powershift transmission. For example, a drive axle of the work machine can be connected downstream of the powershift transmission.

[0013] The splitter gearbox can, for example, comprise three shafts and six externally toothed clutches, by means of which five forward gears and one reverse gear can advantageously be provided.

[0014] The powershift transmission is preferably arranged directly downstream of the splitter transmission, i.e. the power flow runs directly from the splitter transmission to the powershift transmission without any intermediate components such as additional transmission groups or gear ratios being provided.

[0015] The powershift transmission comprises a first shaft, a second shaft, a third shaft and a fourth shaft.

[0016] The second, third, and fourth shafts are advantageously arranged axially offset and coaxial with one another. The first shaft is advantageously arranged parallel to the second, third, and fourth shafts.

[0017] The powershift transmission further comprises a first pair of gears and a second pair of gears. Each pair of gears advantageously consists of two meshing spur gears, one of which can be designed as a fixed gear and one as a loose gear.

[0018] The powershift transmission also includes a first powershift clutch and a second powershift clutch. The first powershift clutch and the second powershift clutch can preferably be designed as wet-running or dry-running multi-plate clutches. Powershift clutches have the advantage that transmission elements to be shifted, such as shafts or gears, do not need to be synchronized before the shifting process.

[0019] Finally, the powershift transmission also includes a first shifting element, a second shifting element, and a third shifting element, which are advantageously not designed to be powershiftable. This makes the first shifting element, the second shifting element, and the third shifting element comparatively more cost-effective and compact, but requires speed synchronization of the transmission elements to be shifted before the shifting process.

[0020] The drive connection of the powershift transmission to the splitter transmission is made, among other things, via the first output of the splitter transmission, which can be directly connected to the first shaft of the powershift transmission.

[0021] The term "directly driveable" or the synonymous term "directly drivable" is understood in the context of the invention to mean that no gear ratios are provided between the drive-connectable elements, meaning that neither a speed conversion nor a torque conversion occurs between the elements. A shifting element or powershift element, however, is provided to drive-connect the two elements so that one element can be driven by the other.

[0022] The first output of the splitter transmission is preferably designed as an output shaft which can be directly connected to the first shaft of the powershift transmission.

[0023] According to the invention, it is now provided that the splitter transmission further comprises a second output via which the second shaft of the powershift transmission can be directly driven.

[0024] Thus, there are two different outputs of the splitter gearbox, via which the first shaft and the second shaft of the powershift gearbox can be driven.

[0025] Advantageously, the first output and the second output have different speeds when the same gear is engaged in the splitter gearbox.

[0026] The invention therefore takes advantage of the fact that the downstream powershift transmission can be constructed comparatively compactly and lightweight by coupling the first output of the splitter transmission or the second output of the splitter transmission to the powershift transmission as needed—i.e., by using the speed of the first output or the speed of the second output as needed—while simultaneously providing a comparatively large number of selectable gear ratios. Using two different input speeds via the first output or the second output, respectively, makes it possible to eliminate one gear ratio in the powershift transmission without reducing the number of available gear ratios.

[0027] According to a preferred embodiment of the invention, it is provided that the second output is aligned coaxially with the second shaft and is connected to the second shaft in a rotationally fixed manner in the axial direction via a connecting piece.

[0028] This results in the advantage that the splitter gearbox does not require a second output shaft, which is generally not provided for commercially available splitter gearboxes. Instead, an idler gear of the splitter gearbox is used as the second output. The speed and torque are tapped via the connecting piece from the idler gear of the splitter gearbox. Thus, a commercially available splitter gearbox can be used to create the group gearbox according to the invention. This advantageously avoids comparatively costly new developments, which may only be produced in small quantities and thus have a high unit price.

[0029] The connecting piece can advantageously be cup-shaped or disc-shaped and can be connected to the idler gear in a rotationally fixed manner, for example, via a flange connection. A welded connection is also conceivable for connecting the connecting piece to the idler gear.

[0030] A one-piece design of the connecting piece with the idler gear is also conceivable and preferred, in which case, when using an already known splitter gear with only one intended output, the corresponding idler gear of the known splitter gear must be replaced by a corresponding idler gear connected in one piece with the connecting piece.

[0031] Furthermore, the connecting piece can alternatively or additionally also be connected in one piece to the second shaft or can be connected to the second shaft via a spline.

[0032] According to a further preferred embodiment of the invention, it is provided that the first shaft can be coupled to the first output via the first powershift clutch and the third shaft can be coupled to the second shaft via the second powershift clutch, wherein a first wheel of the first pair of wheels and a first wheel of the second pair of wheels are arranged on the first shaft, a second wheel of the first pair of wheels is arranged on the third shaft and a second wheel of the second pair of wheels is arranged on the fourth shaft.

[0033] This embodiment has proven to be particularly efficient in terms of being able to represent the largest possible number of gear steps while ensuring the highest possible efficiency of the powershift transmission.

[0034] According to a particularly preferred embodiment of the invention, it is provided that the first wheel of the first pair of wheels is designed as a loose wheel and can be coupled to the first shaft via the first switching element, wherein the second wheel of the first pair of wheels is designed as a fixed wheel and can be coupled to the fourth shaft via the second switching element, and wherein the second wheel of the second pair of wheels is designed as a loose wheel and can be coupled to the fourth shaft via the third switching element.

[0035] This further facilitates the representation of a large number of gear steps while at the same time ensuring the highest possible efficiency of the powershift transmission.

[0036] According to a further preferred embodiment of the invention, it is provided that four gear stages can be represented via the powershift transmission.

[0037] It has been shown that the representation of four gear stages is possible with a comparatively high efficiency of each of the four gear stages.

[0038] According to a particularly preferred embodiment of the invention, it is provided that a drive path of the first gear stage runs from the second output via the second shaft, the second powershift clutch, the third shaft, the first pair of gears, the first shifting element, the first shaft, the second pair of gears, the third shifting element and the fourth shaft.

[0039] The drive path of the first gear thus runs over only two pairs of wheels, which ensures a comparatively high level of efficiency.

[0040] According to a further particularly preferred embodiment of the invention, it is provided that a drive path of the second gear stage runs from the first output via the first powershift clutch, the first shaft, the second pair of gears, the third shift element and the fourth shaft.

[0041] Since the drive path of the second gear stage only runs via a single pair of wheels, namely the second pair of wheels, a particularly high level of efficiency can be guaranteed here.

[0042] According to a further particularly preferred embodiment of the invention, it is provided that a drive path of the third gear stage runs from the second output via the second shaft, the second powershift clutch, the third shaft, the second shifting element and the fourth shaft.

[0043] The drive path of the third gear stage therefore has no gear ratio at all, which ensures even greater efficiency.

[0044] According to a further particularly preferred embodiment of the invention, it is provided that a drive path of the fourth gear stage runs from the first output via the first powershift clutch, the first shaft, the first shifting element, the first pair of gears, the second shifting element and the fourth shaft.

[0045] The drive path of the fourth gear also runs via only a single pair of wheels, namely the first pair of wheels, which ensures particularly high efficiency for the fourth gear as well.

[0046] Due to the multiple uses of the elements of the powershift transmission, comparatively fewer components are required overall, which means that the powershift transmission remains comparatively compact, lightweight and cost-effective.

[0047] According to a further preferred embodiment of the invention, it is provided that an output of the powershift transmission is designed as a bevel pinion.

[0048] This offers the advantage that a differential, such as a differential of a driven axle, can be driven particularly easily via the output. The axle can, for example, be designed as the rear axle of the work machine and be directly connected to the powershift transmission via the bevel pinion.

[0049] According to a further preferred embodiment of the invention, it is provided that the powershift transmission comprises a switchable all-wheel drive.

[0050] This offers the advantage of improving the off-road capability of a vehicle equipped with a range transmission. Furthermore, engaging all-wheel drive also ensures greater traction on the ground, which can be particularly advantageous for agricultural machinery, as it allows the use of a comparatively larger plow, for example.

[0051] When all-wheel drive is not required, it can be switched off again to prevent the efficiency of the powershift transmission from being permanently adversely affected and thus to keep fuel consumption low.

[0052] Finally, the invention relates to a work machine comprising a group transmission according to the invention. Thus, the advantages of the invention also result in the work machine according to the invention.

[0053] The work machine is preferably an agricultural vehicle, in particular an agricultural tractor.

[0054] The invention is explained below by way of example with reference to embodiments shown in the figures.

[0055] It shows: Fig. 1 shows, by way of example and schematically, a possible embodiment of a powershift group transmission according to the invention for a Fig. 1 (not shown) working machine.

[0056] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0057] Fig. 1 shows, by way of example and schematically, a possible embodiment of a powershift group transmission 100 according to the invention for a Fig. 1 (not shown) work machine. The work machine is, for example, an agricultural vehicle, namely a tractor.

[0058] The group transmission 100 comprises a splitter transmission 110 in countershaft design and a powershift transmission 120 which is connected downstream of the splitter transmission 110 and is also designed in countershaft design.

[0059] The splitter gear 110 comprises, for example, three shafts 111, 114, 115, six externally toothed clutches 117, 117', 118, 118', 119, 119' and several spur gears 112, 116 by means of which, for example, five forward gears and one reverse gear can be represented.

[0060] The powershift transmission 120, in turn, comprises a first shaft 131, a second shaft 132, a third shaft 133, and a fourth shaft 134, as well as a first gear pair 141 and a second gear pair 142, and a first powershift clutch 151 and a second powershift clutch 152. Finally, the powershift transmission 120 also comprises a first shifting element 154, a second shifting element 155, and a third shifting element 156.

[0061] The splitter transmission 110 has a first output 111, by means of which the first shaft 131 of the powershift transmission 120 can be driven via the first powershift clutch 151. Furthermore, the splitter transmission 110 also has a second output 112, by means of which the second shaft 132 of the powershift transmission 120 can be driven.

[0062] The splitter gearbox 110 is, for example, a splitter gearbox 110 known per se, which does not have any modifications or adaptations in order to be usable for the group gearbox 100 according to the invention.

[0063] For example, the second output 112 is aligned coaxially with the second shaft 132 and is connected to the second shaft 132 in a rotationally fixed manner in the axial direction via a connecting piece 113.

[0064] The connecting piece 113 is, for example, pot-shaped and is connected to the second output 112 in a rotationally fixed manner by means of a flange connection. The connecting piece 113 is formed integrally with the second shaft 132.

[0065] A third output 114 of the splitter gearbox 110 is simultaneously designed as a fourth shaft 114 of the powershift gearbox 120 and represents a direct drive from a drive unit 180, for example a diesel engine 180, of the work machine. The fourth shaft 114 is also one of the three shafts 111, 114, 115 of the splitter gearbox 110. For example, a hydraulic arrangement 190 can be driven via the fourth shaft 114 and a power take-off shaft 192 via a clutch 191.

[0066] As can be seen, the first powershift clutch 151 and the first shifting element 154 are arranged on the first shaft 131. Furthermore, a first gear 141' of the first gear pair 141 and a first gear 142' of the second gear pair 142 are arranged on the first shaft 131. The first gear 141' of the first gear pair 141 is designed as a loose gear, and the first gear 142' of the second gear pair 142 is designed as a fixed gear.

[0067] The second shaft 132 and the third shaft 133 are arranged coaxially to one another and can be connected to one another by the second powershift clutch 152. A second gear 141" of the first gear pair 141 is also arranged on the second shaft 133. The second gear 141" of the first gear pair 141 is designed as a fixed gear, and the second gear 142" of the second gear pair 142 is designed as a loose gear.

[0068] The fourth shaft 134 is arranged coaxially with the third shaft 133 and can be connected to the third shaft 133 via the second shifting element 155. A second gear 142" of the second gear pair 142 and the third shifting element 156 are also arranged on the fourth shaft 134.

[0069] The exemplary powershift transmission 120 is designed to represent four gear stages.

[0070] A drive path of the first gear stage runs, for example, from the second output 112 via the second shaft 132, the second powershift clutch 152, the third shaft 133, the first gear pair 141, the first shifting element 154, the first shaft 131, the second gear pair 142, the third shifting element 156 and the fourth shaft 134.

[0071] A drive path of the second gear stage runs, for example, from the first output 111 via the first powershift clutch 151, the first shaft 131, the second gear pair 142, the third shift element 156 and the fourth shaft 134.

[0072] A drive path of the third gear stage runs, for example, from the second output 112 via the second shaft 132, the second powershift clutch 152, the third shaft 133, the second shift element 155 and the fourth shaft 134.

[0073] A drive path of the fourth gear stage runs, for example, from the first output 111 via the first powershift clutch 151, the first shaft 131, the first shifting element 154, the first gear pair 141, the second shifting element 155 and the fourth shaft 134.

[0074] An output of the powershift transmission 120 is designed as a bevel pinion 160 and drives a differential 162 of a rear axle 161 of the working machine.

[0075] By means of a switchable all-wheel drive 170 of the powershift transmission 120, a front axle (not shown in Fig. 1) the working machine can be driven. Reference symbol 100 Powershift group transmission 110 splitter gearbox 111 first output, splitter gear shaft 112 second exit 113 connecting piece 114 fourth shaft, shaft of the splitter gear 115 Splitter gear shaft 116 Spur gear of the splitter gear 117 Clutch 117' clutch 118 Clutch 118' coupling 119 Clutch 119' coupling 120 powershift transmissions 131 first wave 132 second wave 133 third wave 134 fourth wave 141 first pair of wheels 141' first wheel of the first pair of wheels 141" second wheel of the second pair of wheels 142 second pair of wheels 142' first wheel of the second pair of wheels 142" second wheel of the second pair of wheels 151 first powershift clutch 152 second powershift clutch 154 first switching element 155 second switching element 156 third switching element 160 bevel pinion 161 rear axle 162 Differential 170 all-wheel drive 180 drive unit; diesel engine 190 Hydraulic arrangement 191 Clutch 192 Power take-off shaft

Claims

[1] Powershift group transmission (100) for a working machine, comprising a splitter gearbox (110) in countershaft design and a powershift gearbox (120) in countershaft design connected downstream of the splitter gearbox (110), wherein the powershift transmission (120) comprises a first shaft (131), a second shaft (132), a third shaft (133) and a fourth shaft (134), a first pair of gears (141) and a second pair of gears (142), a first powershift clutch (151) and a second powershift clutch (152) and a first shifting element (154), a second shifting element (155) and a third shifting element (156) and wherein the splitter transmission (110) has a first output (111) via which the first shaft (131) of the powershift transmission (120) can be directly driven, characterized by , that the splitter transmission (110) further comprises a second output (112) via which the second shaft (132) of the powershift transmission (120) can be directly driven. [2] Group transmission (100) according to claim 1, characterized by that the second output (112) is aligned coaxially with the second shaft (132) and is connected to the second shaft (132) in a rotationally fixed manner in the axial direction via a connecting piece (113). [3] Group transmission (100) according to at least one of claims 1 and 2, characterized by , that the first shaft (131) can be coupled to the first output (111) via the first powershift clutch (151) and the third shaft (133) can be coupled to the second shaft (132) via the second powershift clutch (151), wherein a first wheel (141') of the first pair of wheels (141) and a first wheel (142') of the second pair of wheels (142) are arranged on the first shaft (131), a second wheel (141") of the first pair of wheels (141) is arranged on the third shaft (133), and a second wheel (142') of the second pair of wheels (142) is arranged on the fourth shaft (134). [4] Group transmission (100) according to claim 3, characterized by , that the first wheel (141') of the first pair of wheels (141) is designed as a loose wheel and can be coupled to the first shaft via the first switching element (154), wherein the second wheel (141") of the first pair of wheels (141) is designed as a fixed wheel and can be coupled to the fourth shaft (134) via the second switching element (155) and wherein the second wheel (142') of the second wheel pair (142) is designed as a loose wheel and can be coupled to the fourth shaft (134) via the third switching element (156). [5] Group transmission (100) according to at least one of claims 1 to 4, characterized by that four gear stages can be represented via the powershift transmission (120). [6] Group transmission (100) according to claim 5, characterized by that a drive path of the first gear stage runs from the second output (112) via the second shaft (132), the second powershift clutch (152), the third shaft (133), the first pair of gears (141), the first shifting element (154), the first shaft (131), the second pair of gears (142), the third shifting element (156) and the fourth shaft (134). [7] Group transmission (100) according to at least one of claims 5 and 6, characterized by that a drive path of the second gear stage runs from the first output (111) via the first powershift clutch (151), the first shaft (131), the second pair of gears (142), the third shift element (156) and the fourth shaft (134). [8] Group transmission (100) according to at least one of claims 5 to 7, characterized bythat a drive path of the third gear stage runs from the second output (112) via the second shaft (132), the second powershift clutch (152), the third shaft (133), the second shifting element (155) and the fourth shaft (134). [9] Group transmission (100) according to at least one of claims 5 to 8, characterized by that a drive path of the fourth gear stage runs from the first output (111) via the first powershift clutch (151), the first shaft (131), the first shifting element (154), the first pair of gears (141), the second shifting element (155) and the fourth shaft (134). [10] Group transmission (100) according to at least one of claims 1 to 9, characterized by that an output of the powershift transmission (120) is designed as a bevel pinion (160). [11] Group transmission (100) according to at least one of claims 1 to 10, characterized by that the powershift transmission (120) comprises a switchable all-wheel drive (170). [12] Working machine comprising a group transmission (100) according to at least one of claims 1 to 11.

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