Transmission device and method for agricultural vehicles

Abstract

A tractor transmission (10) includes a range gearbox (12) having an input shaft (26) and an output shaft (28), the input shaft (26) being driven by a prime mover (18) through a main clutch (32). An auxiliary drive shaft (14) is driven by the prime mover independently of the input shaft. A torque fill drive system (16) is operable between the auxiliary drive shaft (14) and the output shaft (28) of the range gearbox. The system (16) includes a torque fill clutch (74) and is operable to transfer torque from the auxiliary drive shaft to the output shaft of the range gearbox when the torque fill clutch (74) is engaged. In use, when drive to the input shaft is interrupted to change gear, the torque fill clutch (74) is engaged to transfer drive from the auxiliary drive shaft to the output shaft and maintain vehicle momentum. The system can transfer torque to the output shaft (28) via an intermediate shaft (30) of the range gearbox or via a ground speed PTO drive.

Description

Technical Field

[0001] The present invention relates to a transmission device for an agricultural vehicle, and more particularly to a transmission device for an agricultural vehicle such as a tractor having different gear ranges. Background Art

[0002] Tractor transmissions often have a large number of gears and usually have several speed gears and several gear ranges. For example, there may be four gears 1, 2, 3, and 4 from slow to fast, and four ranges A, B, C, and D from low to high.

[0003] The gear ranges are also called operating zones and help optimize the efficiency of the engine and transmission, resulting in a more economical drive. Each operating zone can start from zero and provide infinitely variable speed adjustment. In one known example, the transmission has four operating zones, for example:

[0004] Workspace A

[0005] For heavy traction / special crops

[0006] 0-9 km / h

[0007] For the heaviest work, such as slow-speed tillage or special crop harvesting.

[0008] Ideal when high traction is required continuously or precise speed regulation is required.

[0009] Extremely high traction in PTO driven trailer situations.

[0010] Workspace B

[0011] For field work

[0012] 0-18 km / h

[0013] General field working range

[0014] Ideal for everything from seeding and quick tillage to different forage operations.

[0015] Easily control different operations (such as harvesting speed).

[0016] Also suitable for transportation in forests.

[0017] Workspace C

[0018] For fast work

[0019] 0-27 km / h

[0020] Ideal for transport in field conditions.

[0021] Suitable for many municipal applications.

[0022] Efficient startup under heavy load conditions.

[0023] Work Area D

[0024] For road transport

[0025] 0-50 km / h

[0026] Ideal for high-speed road transport.

[0027] In a known device, a range gearbox has an input shaft that can be selectively driven by a prime mover of a vehicle via a clutch device. Two or more input stage gears are rotatably mounted to the input shaft, and a first gear selection device is operable to selectively lock any one of the input stage gears to the input shaft to transmit drive between the input shaft and the selected input stage gear. An output shaft is arranged parallel to the input shaft. The output shaft has two or more output stage gears rotatably mounted to the output shaft, and a second gear selection device is provided to selectively lock any one of the output stage gears to the output shaft to transmit drive between the selected output stage gear and the output shaft. An intermediate shaft is arranged between the input shaft and the output shaft and is parallel to the input shaft and the output shaft. The intermediate shaft carries a number of fixed gears that are constantly meshed with the selectable input stage gears and the output stage gears so that when each of the input stage gears and the output stage gears is selected, torque is transmitted from the input shaft to the output shaft via the selected gear and the intermediate shaft. By selecting different combinations of input stage gears and output stage gears, various gear ratios can be provided. Typically, a range gearbox shifts the input stage gears and the output stage gears independently and / or sequentially.

[0028] It is also known to provide a tractor with a power take-off (PTO). A tractor may have more than one PTO, such as a front PTO and a rear PTO.

[0029] Generally speaking, the one or more PTOs are shafts driven by the prime mover of the tractor to transmit mechanical drive to the attached implements, such as baler rotary harrows, fertilizer spreaders, spray pumps. Implement manufacturers currently manufacture tractors and implements to run at one of three standard speeds, namely 540rpm, 1000rpm and ground speed. The term "ground speed" refers to the rotation rate of the PTO output shaft being proportional to the speed at which the tractor travels on the ground. Since implements are manufactured according to these standards, tractors must be equipped with a PTO output shaft that rotates at the required speed. PTO gear trains with different speed options (e.g., 1000rpm, 540rpm, ground speed) have been developed. For ease of reference, a PTO device intended to provide output at one or more set speeds (e.g., 540rpm, 1000rpm) will be referred to as an "independent" PTO hereinafter because the speed of the PTO output shaft is independent of the ground speed of the vehicle.

[0030] In the case of an independent PTO, the drive to the PTO is usually obtained from an auxiliary drive shaft driven by a free prime mover. In this case, a PTO gearbox is provided that will produce a desired PTO output shaft output speed at a given engine speed. The gearbox can include a variable speed gearbox that allows the user to select different PTO output shaft speeds. The selected engine speed is selected by the vehicle manufacturer, and is usually a speed close to the maximum engine speed, thereby allowing the engine speed to decrease as the load on the PTO output shaft increases. In the case of a relatively low load on the PTO output shaft, there is no need for a torque backup provided by running the engine at a high speed. Therefore, running the engine at a high speed is not efficient. In order to overcome this problem, tractor manufacturers often provide a so-called economical PTO drive mode, in which the gear train is arranged to drive the PTO output shaft at a desired speed at an engine speed of about two-thirds of the maximum speed. This improves fuel economy, and the engine runs more quietly at a slower speed.

[0031] To provide a ground speed PTO, drive to the PTO output shaft may be taken from a portion of the vehicle's transmission that rotates at a speed proportional to the vehicle's ground speed. In some known arrangements, drive to the ground speed PTO is taken from an output shaft of a range gearbox.

[0032] Where both independent and ground speed PTO options are provided, these PTOs may utilize a clutch arrangement to selectively engage independent fixed speed drive from an auxiliary shaft or ground speed drive derived from an output shaft of the range gearbox via a common PTO output shaft.

[0033] Modern tractors may also be equipped with power reciprocating transmissions to allow easy switching between forward and reverse travel, as well as power shift transmissions (PS) or continuously variable transmissions or (CV) transmissions, as discussed in more detail below. Where provided, they are typically located in the driveline between the prime mover and the range gearbox, and include a clutch device operable to selectively transmit drive to the input shaft of the range gearbox.

[0034] Tractors are often used in applications that require frequent shifting between forward and reverse gears, such as loading work or tillage work. To avoid repeated disengagement of the clutch, power reciprocating transmissions were developed. Power reciprocating transmissions allow the vehicle driver to change the direction of travel from forward to reverse or vice versa simply by pressing a button or pulling an operating lever. This eliminates the need for the driver to use the clutch pedal to initiate a gear change direction. Some power reciprocating transmissions also allow shifts from neutral to forward gear or neutral to reverse gear to be performed.

[0035] One type of power reciprocating transmission requires hydraulic actuation of the clutch. The performance of this type of power reciprocating transmission is affected by the time it takes the hydraulic actuator to move the clutch pack from its bite point to its fully engaged position. This is called clutch take-up. Changing the duration of this period changes the aggressiveness of clutch take-up and, therefore, the aggressiveness of drive take-up.

[0036] Providing a power reciprocating transmission means that the transmission can provide the same number of forward gears as reverse gears. For a 4-speed, 4-range transmission using a power reciprocating device, this would be described as a "16×16" transmission. Alternatively, the tractor may have a four-range transmission with six speeds, thus having twenty-four speeds, including a power reciprocating device would provide twenty-four forward gears and twenty-four reverse gears or a "24×24" transmission.

[0037] Furthermore, modern tractors are usually equipped with a power shift transmission (PS) or a continuously variable transmission or (CV) transmission.

[0038] A CV transmission can use a belt to transfer power from the tractor engine to the drive wheels or other ground engaging drive devices such as tracks at an essentially infinite number of speeds.

[0039] For simplicity, reference will be made herein to "wheels" or "drive wheels." However, it should be understood that these terms are also intended to encompass other ground engaging devices such as ground engaging tracks that may be used to drive a vehicle across the ground, unless the context requires otherwise.

[0040] The PS transmission operates within a given range of the transmission and allows shifting under load. Typically with a PS transmission, the operator selects the engine speed and the appropriate gear for a particular task, then as the load increases, the engine speed drops and the operator can shift to a more appropriate gear.

[0041] A PS transmission reduces the torque interruption during gear changes to a minimum duration, but nevertheless there is necessarily a brief interruption in the drive to the wheels during the gear change process / gear change as one gear is disengaged and the next gear is engaged.

[0042] When there is a significant load on the vehicle transmission, the interruption of torque delivery to the drive wheels may result in undesirable / uncomfortable operating conditions - such as jerky / intermittent / interrupted vehicle movement. Such undesirable operating conditions are particularly prominent and problematic when there is a significant drag load on the vehicle. For example, when a tractor is pulling a plow, the engagement of the plow with the ground effectively acts as an anchor and slows the vehicle's forward motion. When drive is temporarily interrupted during a gear shift, the vehicle tends to decelerate very quickly. However, when the gear change is completed and drive is resumed, the drag load is quickly overcome. This can result in undesirable intermittent operating and driving characteristics, and may cause undue and excessive wear on components of the transmission and drivetrain, which can lead to component fatigue and early failure. Other implements often used with tractors may result in drag loads similar to towing a heavy trailer (especially uphill).

[0043] A PS transmission allows gear changes under load with minimal interruption of the torque transmitted between the engine and the drive wheels. This is usually achieved by using a selectively engageable clutch device for each gear, or a pair of clutches for the two drive shafts connected to the respective gear sets, and a further clutch device to connect the gears to the output shaft. However, there is usually still a period during which the torque transmitted between the engine and the wheels is briefly interrupted. Interruption of the wheel drive is a particular problem when changing between range gears.

[0044] It is an object of the present invention to provide a vehicle transmission which overcomes or at least alleviates the problems of known vehicle transmissions. In particular, it is an object of the present invention to provide a transmission which reduces interruption of drive or power flow to the drive wheels during range gear changes.

[0045] Another object of the present invention is to provide a method of operating such a vehicle transmission so as to overcome or at least alleviate the problems of known vehicle transmissions. Summary of the invention

[0046] According to one aspect of the present invention, a transmission device for agricultural vehicles is provided, the transmission device including a range gearbox having an input shaft and an output shaft, the input shaft being drivably connected to a prime mover in a vehicle in which the transmission is installed, the output shaft being drivably connected to the input shaft to provide a plurality of gear ratios and being operable in use to provide drive to at least one ground engaging member of the vehicle, the transmission also including an auxiliary drive shaft drivably connected to the prime mover independently of the input shaft of the range gearbox, wherein the transmission includes a torque filling drive system operating between the auxiliary drive shaft and the output shaft of the range gearbox, the torque filling drive system including a torque filling clutch and being configured to transfer torque from the auxiliary drive shaft to the output shaft of the range gearbox when the torque filling clutch is engaged in use.

[0047] Advantageously, in a transmission according to this aspect of the invention, the torque fill clutch may be engaged to transfer torque from the auxiliary shaft to the range gearbox output shaft to prevent or at least reduce interruption of drive torque to the drive wheels when the range gearbox shifts between gears.

[0048] In one embodiment, the range gearbox includes a plurality of input-stage gears rotatably mounted to an input shaft and a first gear selection device for selectively locking any one of the input-stage gears to the input shaft to transmit drive between the input shaft and the selected input-stage gear, a plurality of output-stage gears rotatably mounted to an output shaft and a second gear selection device for selectively locking any one of the output-stage gears to the output shaft to transmit drive between the selected output-stage gear and the output shaft, and an intermediate shaft having a plurality of gears for transmitting torque between the input-stage gears and the output-stage gears, wherein the torque-filling drive system is configured to transmit torque to the output shaft of the range gearbox via the intermediate shaft of the range gearbox.

[0049] In one embodiment, the input shaft, output shaft and intermediate shaft in the range gearbox are arranged parallel to each other, and the torque filling drive system includes a torque filling drive shaft arranged parallel to the range gearbox shaft, the torque filling drive system includes a torque filling shaft input drive device for transferring drive from the auxiliary shaft to the torque filling shaft, and a torque filling shaft output drive device for transferring drive from the torque filling shaft to the intermediate shaft of the range gearbox, and the torque filling clutch forms part of the torque filling shaft input drive device or the torque filling output drive device.

[0050] In one embodiment, the range gearbox input shaft is hollow and the auxiliary drive shaft passes through the range gearbox input shaft, the auxiliary drive shaft exits the range gearbox input shaft at a first side of the range gearbox, and the torque filling shaft input drive device is located on the first side of the range gearbox for cooperating with the auxiliary drive shaft. In this case, the torque filling shaft output drive device can be located on the side of the input stage gear opposite to the torque filling shaft input drive device. The torque filling shaft output drive device can include a series of meshing gears, the series of meshing gears including at least a first gear mounted around the torque filling drive shaft and a second gear fixed to rotate with the intermediate shaft, and the torque filling clutch is operable to selectively connect and disconnect the first gear with the torque filling drive shaft. In a different embodiment, the torque filling clutch forms part of the torque filling shaft input drive device. In this embodiment, the torque filling shaft input drive device can include a series of meshing gears, including at least a first gear fixed to rotate with the auxiliary shaft and including another gear, wherein the torque filling clutch is operable to selectively connect and disconnect the other gear with the torque filling drive shaft. The torque filler shaft output drive may include a gear fixed for rotation with the torque filler drive shaft, the gear being in constant meshing engagement with one of the input stage gears of the range gearbox, and wherein one of the input stage gears is in constant meshing engagement with a gear fixed for rotation with the range gearbox intermediate shaft.

[0051] In the case where the torque filling drive system is configured to transmit torque to the range transmission output shaft via the range transmission intermediate shaft, the torque filling drive system may include a series of meshing gears, a first meshing gear of the meshing gears being fixed to rotate with the auxiliary drive shaft, and the torque filling clutch being operable to selectively couple and decouple the last gear in the series with the range transmission intermediate shaft.

[0052] In one embodiment, the transmission includes a ground speed PTO transmission shaft that can be drivingly engaged with the interval transmission output shaft through a ground speed PTO clutch, and the torque filling drive system is operable to transfer torque from the auxiliary shaft to the interval transmission output shaft via the ground speed PTO transmission shaft and the ground speed PTO clutch. In this embodiment, the torque filling system may include a gear train for transmitting drive between the auxiliary drive shaft and the ground speed PTO transmission shaft, and the torque filling clutch is operable to selectively connect and disconnect the last gear of the gear train with the ground speed PTO transmission shaft. The torque filling drive system may also have an additional clutch that is operable to drivingly connect the first gear in the gear train to the auxiliary drive shaft. The additional clutch may be an independent PTO clutch.

[0053] The transmission may also include a PS transmission and / or a reciprocating transmission located upstream of the range transmission.

[0054] According to another aspect of the present invention, there is provided an agricultural vehicle comprising a transmission arrangement as described above. The vehicle may comprise a prime mover operatively connected to a range speed input shaft and an auxiliary drive shaft. The vehicle may be an agricultural tractor.

[0055] According to a further aspect of the invention there is provided a method of operating an agricultural vehicle according to the previously defined aspect, the method comprising engaging a torque fill clutch to transfer torque from an auxiliary shaft to a range gearbox output shaft during a range gear change.

[0056] The method may include disengaging the torque fill clutch once the gear change is completed.

[0057] In the case where torque is transferred from the auxiliary shaft to the output shaft of the range gearbox via the intermediate shaft of the range gearbox, the step of engaging the torque filling clutch to transfer torque from the auxiliary shaft to the output shaft of the range gearbox can only be performed during the input stage range gear change.

[0058] According to yet another aspect of the present invention, there is provided a method of operating an agricultural vehicle as defined above, the method comprising:

[0059] a) interrupting the drive to the input shaft of the range gearbox shaft while maintaining the drive to the auxiliary drive shaft;

[0060] b) switching between the interval gears while interrupting the drive to the input shaft;

[0061] c) once the gear change is complete, reengaging drive to the input shaft;

[0062] d) engaging the torque fill clutch to transfer torque from the auxiliary shaft to the range gearbox output shaft at least during a portion of the time when drive to the input shaft is interrupted.

[0063] The method may include engaging the torque fill clutch in step d) just after drive from the prime mover to the range gearbox is interrupted, just before drive from the prime mover to the range gearbox is interrupted, or while drive from the prime mover to the range gearbox is interrupted. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0065] Figure 1 is a schematic diagram of a tractor including a transmission arrangement according to an aspect of the present invention;

[0066] Figure 2 is Figure 1 A schematic diagram of a first embodiment of a transmission device according to one aspect of the present invention used in a tractor;

[0067] Figure 3 is Figure 1 A schematic diagram of a second embodiment of a transmission device according to one aspect of the present invention used in a tractor;

[0068] Figure 4 is Figure 1 A schematic diagram of a third embodiment of a transmission device according to an aspect of the present invention for use in a tractor; and

[0069] Figure 5 is Figure 1 FIG. 4 is a schematic diagram of a fourth embodiment of a transmission device according to an aspect of the present invention for use in a tractor.

[0070] The drawings are provided by way of reference only and are to be acknowledged as not being drawn to scale. DETAILED DESCRIPTION

[0071] Figure 1 A tractor 1 is shown which comprises a transmission arrangement 10 according to the invention, an exemplary embodiment of which is shown in FIG. Figures 2 to 5 The transmission arrangement 10 may be housed in a common housing, or in a plurality of housings attached to each other to form a single common housing, not shown. The common housing is suitable for attachment to an axle, particularly a rear axle, and may form part of the chassis or may be a structural load in the case of a tractor transaxle.

[0072] Reference Figure 2 , which shows an exemplary schematic diagram of a transmission device 10 according to a first embodiment of the present invention.

[0073] The transmission arrangement includes a range gearbox, generally indicated at 12 , an auxiliary drive shaft 14 , and a torque fill drive system, generally indicated at 16 , selectively operable to transfer torque from the auxiliary drive shaft to an intermediate shaft of the range gearbox, as will be described in greater detail below.

[0074] It should be understood that the term "range gearbox" refers to a functional unit of a transmission for providing a number of selectable gear ratios. The term does not imply that the unit is located in a housing or box separate from other functional units in the transmission, which, as mentioned above, may be accommodated in a common housing.

[0075] Figure 2 Also shown are a prime mover 18 of the vehicle, a power reciprocating unit 20 and a PS unit 22 which may optionally form part of a transmission according to the present invention.

[0076] Prime mover 18 is responsible for power generation for the vehicle and may, for example, comprise an internal combustion engine such as a diesel engine or a generator powering an electric motor to provide electrical drive, or indeed prime mover 26 may be a hybrid drive system such as a diesel electric machine.

[0077] The prime mover may be of any suitable design and / or capability to drive the transmission arrangement 10 and ultimately provide power to the drive wheels and any other systems on the vehicle, such as a PTO.

[0078] The power reciprocating unit 20 and the PS unit 22 may also be of any suitable type and are therefore not shown in detail. In practice, the power reciprocating unit 20 and / or the PS unit 22 may be omitted or replaced by other functionally equivalent units. For example, the PS unit may be replaced by a CV transmission.

[0079] The auxiliary drive shaft 14 is driven by the prime mover and is used to provide drive for auxiliary systems of the vehicle, such as the vehicle's hydraulic system and / or PTO. These auxiliary systems do not form part of the present invention and are not described in detail. However, a PTO clutch for selectively coupling the auxiliary drive shaft 14 to an independent PTO gear train is shown at 24. An independent PTO transmission shaft 25 is schematically shown as being associated with an output or downstream portion 24a of the independent PTO clutch 24. When the independent PTO clutch is engaged, drive is transmitted from the auxiliary drive shaft 14 to the independent PTO transmission shaft 25, and from there to the PTO output shaft (also not shown) through an independent PTO gearbox (not shown). Typically, the auxiliary shaft is always driven, the prime mover is running and rotates in a constant direction, which direction may correspond to the direction of the output shaft of the prime mover, for example, clockwise.

[0080] The range gearbox 12 comprises an input shaft 26, an output shaft 28 and an intermediate shaft 30. All three shafts are arranged so that their axes are parallel to each other and to the auxiliary drive shaft 14.

[0081] The input shaft 26 is drivingly coupled to the prime mover through the power reciprocating device 20 and the PS unit 22, which include a clutch arrangement for selectively transmitting drive to the range gearbox input shaft 26. The clutch arrangement will typically include a forward clutch in the power reciprocating unit 20, which is schematically shown at 32 and will be referred to as a master clutch for simplicity. However, it should be understood that references to a master clutch herein (including the claims) are intended to encompass any suitable clutch operable to engage and disengage drive from the prime mover to the input shaft 26.

[0082] In this embodiment, the input shaft 14 is a hollow shaft mounted concentrically around the auxiliary drive shaft, but this is not required.

[0083] The first input stage gear 34 and the second input stage gear 36 are each mounted around the input shaft. The first gear selection system includes a synchronizer 38, which is operable to selectively lock one or the other of the input stage gears 34, 36 to rotate with the input shaft. When the input stage gear 34, 36 is rotationally locked to the input shaft 14 by the synchronizer (i.e., the gear is selected), torque can be transferred from the input shaft 14 to the selected input stage gear. When the input stage gear 34, 36 is not selected, it can rotate freely around the input shaft so that torque is not transferred between the two.

[0084] Similarly, the first output stage gear 40 and the second output stage gear 42 are each mounted around the output shaft 28. The second gear selection system includes another synchronizer 44, which is operable to selectively lock one or the other of the output stage gears 40, 44 to rotate with the output shaft. When the output stage gear 40, 42 is rotationally locked to the output shaft 14 by the other synchronizer 44 (i.e., the gear is selected), torque can be transferred from the selected output stage gear to the output shaft 28. When the output stage gear 40, 42 is not selected, it can rotate freely around the output shaft 28, so that torque is not transferred between the two.

[0085] The intermediate shaft 30 has several gears permanently fixed to rotate with the shaft. These gears include:

[0086] a first countershaft gear 46 in constant meshing engagement with the first input stage gear 34;

[0087] a second countershaft gear 48 in constant meshing engagement with the second input stage gear 36 and with the first output stage gear 40; and

[0088] A third countershaft gear 50 which is in constant meshing engagement with the second output stage gear 42 .

[0089] The intermediate shaft 30 and the intermediate shaft gears 46, 48, 50 are operable to transfer drive between a selected one of the input stage gears 34, 36 and a selected one of the output stage gears 40, 42 to form a drive path from the input shaft to the output shaft. Thus, in use, when one of the input stage gears 34, 36 is selected and one of the output stage gears 40, 42 is selected and the main clutch 32 is engaged so that the input shaft 26 is driven, drive / torque will be transmitted to the output shaft 28 via the selected input stage gears 34, 36, the intermediate shaft 30 and the selected output stage gears 40, 42. The output shaft 28 is drivingly connected to the rear axle (as schematically indicated at 52) ​​to drive the rear wheels, and optionally, to the front axle (as schematically indicated at 54) of the vehicle to drive the front wheels. By selecting different combinations of input stage gears and output stage gears, four different gear ratios are provided. In the present embodiment, the range gearbox provides four ranges A, B, C and D. Section A is provided by selecting the second input stage gear 36 and the second output stage gear 42, section B is provided by selecting the first input stage gear 34 and the second output stage gear 42, section C is provided by selecting the second input stage gear 36 and the first output stage gear 40, and section D is provided by selecting the first input stage gear 34 and the first output stage gear 40.

[0090] In order to switch or change the interval gear, the main clutch 32 is disengaged so that the drive to the input shaft 14 is interrupted so that the gear change synchronizers 38, 44 can be actuated. When switching between the intervals A and B and between the intervals C and D, only the first gear selection system including the input stage synchronizer 38 needs to be actuated. When switching between the intervals B and C, both gear selection systems including the input stage synchronizer 38 and the output stage synchronizer 44 are actuated. In this case, the two synchronizers will usually be actuated sequentially.

[0091] When the drive to the input shaft 14 is interrupted in order to switch the range gear, the drive to the drive wheels will also be interrupted, as discussed above. To reduce this effect, the torque filling drive system 16 is operable to transfer torque from the auxiliary drive shaft 14 to the output shaft 28 of the range gearbox when the drive to the input shaft of the range gearbox is interrupted during the gear change. In this embodiment, the torque filling drive system transfers the drive to the output shaft 28 of the range gearbox via the intermediate shaft 30 of the range gearbox.

[0092] The torque filler drive system 16 includes a torque filler shaft 60 arranged parallel to the auxiliary drive shaft 14 and the range gearbox input shaft 26. The torque filler shaft input drive device 62 takes the form of a gear train, which includes a first gear 64 fixed in rotation with the torque filler drive shaft 60, another gear 66 fixed in rotation with the auxiliary drive shaft 14, and an intermediate gear 68 between the first gear 64 and the other gear 66, and the intermediate gear 68 is arranged so that the torque filler drive shaft is driven to rotate whenever the auxiliary drive shaft is driven by the prime mover 18. It should be understood that other means for transmitting drive from the auxiliary drive shaft 14 to the torque filler drive shaft 62 may also be used. For example, a belt system or a chain system may be used instead of using meshing gears.

[0093] The torque filler shaft input drive 62 is located at one end of the torque filler shaft on the far side of the range gearbox 12 relative to the prime mover 18. At the opposite end of the torque filler shaft, which is located on the side of the range gearbox closest to the prime mover 18, is a torque filler shaft output drive 70 for transmitting drive from the torque filler shaft 60 to the intermediate shaft 30 of the range gearbox 12. The torque filler shaft output drive includes a first torque filler shaft output gear 72 mounted about the torque filler shaft 60 and a torque filler clutch 74 for selectively locking the first torque filler shaft output gear to the torque filler shaft 60 when engaged. The first torque filler shaft output gear 72 is drivingly coupled to a torque filler intermediate shaft gear 76, which is rotationally fixed with the range gearbox intermediate shaft 30. The arrangement is configured so that when the torque filler clutch 74 is engaged, torque can be transferred from the auxiliary drive shaft 14 through the torque filler shaft input drive 62 to the torque filler shaft 60, and then through the torque filler clutch 74 to the first torque filler shaft output gear 72 and the torque filler intermediate shaft gear 76 to drive the intermediate shaft 30. If one of the output stage gears 40, 44 in the range gearbox 12 is selected, drive will be transferred from the intermediate shaft 30 to the output shaft 28 of the range gearbox and thence to the drive wheels.

[0094] In normal use when the vehicle is moving, the torque filling clutch 74 is disengaged and drive is transferred from the input shaft 26 to the output shaft 28 via the range gearbox in the usual manner. When it is necessary to change the input stage range gears 34, 36, the drive to the input shaft 26 of the range gearbox is interrupted, for example by disengaging the main clutch 32. However, the drive to the auxiliary drive shaft is maintained, and by engaging the torque filling clutch 74, the drive / torque is transferred from the auxiliary drive shaft 14 to the intermediate shaft 30 of the range gearbox and thus to the output shaft 28 and the drive wheels to maintain the momentum of the vehicle. Once the gear change is completed, the main clutch 32 is reengaged and the torque filling clutch 74 is disengaged. This reduces the effect of torque interruption during the gear shift process, thereby providing a smoother driving experience.

[0095] Although the torque fill system 16 is only operable when switching input stage gears, such as when switching between zones A and B and between zones C and D, these changes often have very significant effects if torque is interrupted. For example, switching between zones A and B often occurs during field work when the vehicle may be subject to high drag loads caused by the implement towed by the vehicle. On the other hand, switching between zones C and D often occurs when the vehicle is traveling on a road and may be towing a heavy trailer or implement uphill, resulting in a high drag load.

[0096] Since the torque filling drive system 16 has a fixed gear ratio, it can only be used when the vehicle is in forward gear and the gear train is configured to rotate the range gearbox intermediate shaft 30 in the appropriate direction for forward drive, which in this case is counterclockwise. In addition, the gear ratio of the torque filling drive system 16 is selected to provide a smooth transition when switching between ranges A and B and between ranges C and D. Therefore, the gear ratio of the torque filling drive system 16 can be selected so that it matches or is between the gear ratios of the top of the A range and the bottom of the B range, and the top of the C range and the bottom of the B range.

[0097] Actuation of the main clutch 32 and the torque fill clutch 74 may be simultaneous or sequential and / or may overlap. If actuation is sequential, the torque fill clutch may be engaged just before or just after drive to the input shaft is interrupted, and the torque fill clutch 74 may be disengaged just before or just after drive to the input shaft is resumed to minimize torque interruption to the drive wheels.

[0098] The torque filling system 16 can be optimally used in transport or highway mode to provide uninterrupted torque and power to the wheels from 5kph to maximum travel speed when switching between intervals C and D. This high torque is necessary for interval gear shifting, which may be required for heavy trailers and hilly conditions. During the switching of input stage interval gears, traction with a traditional transmission may be lost, and the vehicle speed may drop sharply, and the vehicle may even stop when driving uphill. With the help of the torque filling system 16, interval gear shifting can be performed in this context while maintaining the original power of the wheels. The torque filling system is also useful in field mode when switching between intervals A and B.

[0099] Figure 3 and Figure 4 An alternative embodiment of a vehicle transmission according to the invention is illustrated in which a torque filling drive system 16 is operated via an intermediate shaft 30 of a range gearbox 12. The same reference numerals are used to denote features that are the same as or perform the same function as in the previous embodiments. Much of the transmission in these embodiments is the same as that in the first embodiment and will not be described in detail. The only difference is the arrangement of the torque filling drive system 16', 16".

[0100] exist Figure 3 In the illustrated embodiment, the torque filling clutch 74' forms part of the torque filling shaft input drive 62' and is therefore located at the input end of the torque filling shaft 60' furthest from the prime mover. The torque filling shaft input drive 62' includes a first gear 64' rotationally coupled to the input or upstream portion of the torque filling clutch 74' (in this case the clutch cover) and a second gear 66' rotationally fixed to the auxiliary drive shaft. The first gear and the second gear mesh, and the torque filling clutch 74' is operable to lock the first gear rotationally fixed to the torque filling shaft 60' when engaged. Therefore, when the torque filling clutch 74' is engaged, drive is transmitted from the auxiliary drive shaft 14 to the torque filling drive shaft 60'. Likewise, it should be understood that other means for transmitting drive from the auxiliary drive shaft 14 to the torque filling drive shaft 60' may be employed, such as a system of drive belts and / or drive chains. Alternative clutch means may also be employed.

[0101] A torque filler shaft output gear 72', rotationally fixed to the torque filler shaft 62', is located at the other end of the shaft. The torque filler shaft output gear 72' is in constant meshing engagement with the second input stage range gear 36, which itself is in constant meshing engagement with the fixed gear 48 on the range gearbox intermediate shaft 30. Thus, when the torque filler clutch 74' is engaged, drive is transmitted from the auxiliary drive shaft 14 via the torque filler clutch 74' to the torque filler shaft 60' and via the output gear 72', the second input stage range gear 36 and the corresponding intermediate shaft gear 48 to the range gearbox intermediate shaft 30. This embodiment uses relatively few additional components to form the torque filler shaft output drive arrangement 70'.

[0102] like Figure 3 The illustrated torque filling drive system 16 ′ may be used in the same manner as the previously described embodiments to temporarily transfer drive from the auxiliary drive shaft 14 to the drive wheels while shifting input stage range gears by engaging the torque filling clutch 74 ′.

[0103] Figure 4 Yet another arrangement of a torque fill drive system 16" is shown. In this embodiment, there is no torque fill drive shaft. Instead, drive is transmitted from the auxiliary drive shaft to the range gearbox intermediate shaft 30 via a first torque fill gear 66" rotationally fixed to the auxiliary drive shaft 14, a second torque fill gear 76" meshing with the first gear 66", and a torque fill clutch 74" operable to transmit drive from the second gear 76" directly to the range gearbox intermediate shaft 30 when engaged. Likewise, it will be understood that other means for transmitting drive from the auxiliary drive shaft 14 to the intermediate shaft 30 may be employed.

[0104] The torque filling drive system 16 ″ in this embodiment may be used in the same manner as the previous embodiments to temporarily transfer drive / torque from the auxiliary drive shaft 14 to the drive wheels while shifting input stage range gears by engaging the torque filling clutch 74 ″.

[0105] As can be seen from the various embodiments described above, the arrangement of the torque filling drive system 16, 16', 16" can be modified in various ways according to the arrangement requirements to selectively transmit drive from the auxiliary drive shaft 14 to the range gearbox intermediate shaft 30. It should be noted that since the range gearbox intermediate shaft 30 rotates in the opposite direction to the auxiliary shaft 14 during forward driving, the above-mentioned torque filling drive system 16, 16', 16" is configured to be, for example, by using Figure 2 The intermediate gear 68 shown in the torque-filled shaft input drive reverses the drive direction between the auxiliary drive shaft 14 and the intermediate shaft 30 .

[0106] In the embodiment described so far, the drive from the auxiliary shaft to the output shaft of the range gearbox is routed via the range gearbox intermediate shaft, the torque filling system only being engaged when shifting the input stage gear. Figure 5 Another example of a transmission according to the present invention is shown, in which the torque filling drive system 16 ″ can be used when shifting any range gear.

[0107] In such Figure 5 In the illustrated embodiment, the torque fill drive system 16" is operable to transmit drive to the output shaft of the range transmission via a portion of the ground speed PTO driveline, generally indicated at 80. Much of the transmission in this embodiment is the same as that in the first embodiment and will not be described in detail. The same reference numerals are used to identify features that are the same or perform the same function as in the previous embodiment.

[0108] The ground speed PTO drivetrain 80 includes a first ground speed PTO gear 82 rotatably mounted about the range gearbox output shaft 28 and a ground speed PTO clutch 84. The ground speed PTO clutch is operable to couple the first ground speed PTO gear 82 to rotate with the range gearbox output shaft 28 when engaged. The first ground speed PTO gear 82 is drivingly coupled to another ground speed gear 86 fixed to one end of a ground speed PTO transmission shaft 88 non-rotatably via one or more additional gears 90. Thus, when the ground speed PTO clutch 84 is engaged, torque can be transferred between the range gearbox output shaft 28 and the ground speed PTO transmission shaft 88. Other arrangements for transferring drive between the ground speed PTO transmission shaft 88 and the range gearbox output shaft 28 may be employed. The ground speed PTO clutch may be a dog clutch or any other suitable type of clutch.

[0109] The other end 92 of the ground speed PTO transmission shaft 68 is drivingly coupled to the PTO output shaft (not shown). Because it is not related to the present invention, the device is not shown in detail. However, as known in the art, both the independent PTO transmission shaft 25 and the ground speed PTO transmission shaft 88 can be drivingly coupled to the common PTO output shaft via a suitable gear arrangement, at least some of which are selectable. The arrangement is configured so that if the independent PTO clutch 24 is engaged, the PTO output shaft is driven at a set speed, or if the ground speed PTO clutch 84 is engaged, the PTO output shaft is driven at ground speed. In some cases, it is also necessary to select a suitable gear to transmit the drive to the PTO output shaft. For example, the independent PTO power transmission system can include selectable gears that provide different gear ratios between the independent PTO transmission shaft 25 and the PTO output shaft, so that the PTO output shaft can be selectively driven at more than one fixed speed (e.g., 1000rpm, 540rpm, and economy mode). However, if no gear is selected, the drive will not be transmitted to the PTO output shaft even if the independent PTO clutch 24 is engaged.

[0110] The torque fill drive system 16'" includes a drive device for transferring drive from the auxiliary drive shaft 14 to the ground speed PTO transmission shaft. In this embodiment, the drive device is operable to transfer drive from the output side or downstream side 24a of the independent PTO clutch 24 to the ground speed PTO transmission shaft 88, such that torque is only transferred when the independent PTO clutch 24 is engaged. However, in an alternative embodiment, the torque fill drive device can be coupled to the auxiliary drive shaft 14 upstream of the independent PTO clutch 24, such that operation of the torque fill system 16'" does not require actuation of the independent PTO clutch 24.

[0111] The output portion 24a of the independent PTO clutch is drivingly coupled to a gear 94 rotatably mounted about a ground speed PTO transmission shaft 88 via a gear train generally designated 96, which in this case includes a series of meshing gears schematically designated 98 and 100. The torque fill clutch 74'" is operable to drivingly couple the gear 94 to the ground speed transmission shaft 88 when engaged. Thus, when the independent PTO clutch 24 and the torque fill clutch 74'" are engaged, torque can be transferred from the auxiliary drive shaft 14 to the ground speed PTO transmission shaft 88. If the ground speed PTO clutch 84 is also engaged, torque will be transferred from the ground speed PTO transmission shaft 88 to the range transmission output shaft 28.

[0112] As discussed above, the respective drive trains between the independent PTO transmission shaft 25 and the ground speed transmission shaft 88 to the PTO output shaft can each include gears that can be selected and deselected so that if no gear in the associated drive train is selected, the independent PTO clutch 24 and the ground speed PTO clutch 84 can be engaged but do not necessarily transmit drive to the PTO output shaft.

[0113] In normal use when the vehicle is moving, at least the torque fill clutch 74'" is disengaged and drive to the wheels is transferred from the input shaft 26 to the output shaft 28 via the range gearbox in the usual manner. When it is necessary to change the input or output stage range gears 34, 36, 40, 42, the drive to the input shaft 26 of the range gearbox is interrupted, for example by disengaging the main clutch 32. However, drive to the auxiliary drive shaft 14 is maintained and drive is transferred from the auxiliary drive shaft 14 to the output shaft 28 of the range gearbox and thus to the drive wheels to maintain the momentum of the vehicle by engaging the independent PTO clutch 24, the torque fill clutch 74'" and the ground speed PTO clutch 84. Once the gear change is completed, the main clutch 32 is reengaged and at least the torque fill clutch 74'" is disengaged. Using the torque fill system 16'" to temporarily provide drive torque to the loaded wheels while interrupting drive to the input shaft of the range gearbox (torque filling) reduces the impact of torque interruption to the drive wheels during the gear shift process, thereby providing a smoother driving experience.

[0114] Because the torque filling drive system 16'" has a fixed gear ratio, it can only be used when the vehicle is moving forward, and the gear train of the torque filling drive system is configured to transmit drive to the output shaft of the range gearbox in the appropriate rotational direction. The gear ratio of the torque filling drive system 16'" is selected to provide a smooth transition between the top of one range and the bottom of the next range.

[0115] During normal driving of the vehicle, if the PTO in one of the independent PTO clutches 24 and the ground speed PTO clutch 84 is in use, the independent PTO clutch and the ground speed PTO clutch can be engaged. However, if the torque fill clutch 74'" remains disengaged, the use of the PTO will not be affected. Depending on the arrangement of the PTO driveline, if the drive from the ground speed PTO transmission shaft 88 to the PTO output shaft is disengaged, the torque fill system can be actuated when the independent PTO is in use. However, it is not expected that the torque fill system will not be used when the ground speed PTO is in use. But in general, it is expected that the drive from the independent PTO clutch 24 and the ground speed PTO transmission shaft 88 to the PTO output shaft will be disconnected - for example by deselecting certain gears in the PTO driveline, while the torque fill system is still in use.

[0116] Actuation of the main clutch 32 may be synchronized with actuation of the independent PTO clutch 24, the torque fill clutch 74'' and the ground speed PTO clutch 84 simultaneously or sequentially, and / or actuation of the various clutches may overlap. If actuation is sequential, the independent PTO clutch, the torque fill clutch and the ground speed PTO clutch interrupt drive to the range speed input shaft just before or after being engaged, and disengage these clutches just before or after drive to the input shaft is resumed.

[0117] It is contemplated that the torque filling system will include an electronic control system for controlling the torque filling clutches 74, 74', 74", 74'" and at least Figure 5 The illustrated embodiment controls actuation of the independent PTO 24 and the ground speed PTO clutch 84. Thus, each of these clutches may include an actuation system that may be controlled by an electronic control system and may include an electronic actuator and / or a fluid actuator. The electronic control system may include an ECU that is programmed to actuate the torque filling system and the torque filling clutch as needed based on the operating conditions of the vehicle. The control system may include various sensors to provide inputs indicative of the operating conditions of the vehicle. For example, these sensors may include sensors that indicate that a change in interval gear has been requested or required. The control system may also control actuation of the main clutch and coordinate the engagement and disengagement of the torque filling clutches 74, 74', 74", 74'" with the engagement and disengagement of the main clutch. The ECU may be a vehicle ECU or it may be a separate dedicated ECU that communicates with the vehicle ECU, for example, via a CAN BUS interface. The various clutches may be of any suitable type.

[0118] For clarity, Figures 2 to 5 The vehicle transmission shown in has been simplified to show only those details relevant to the present invention. An actual vehicle transmission incorporating the range gearbox 12 and the torque filling drive system 16, 16', 16", 16'" as shown will typically include several additional features or systems, such as one or more PTO gear trains and / or track mode gear trains, and various clutches and / or differentials for transmitting drive from the output shaft of the range gearbox to the rear and / or front wheels of the vehicle. For example, Figures 2 to 4 The embodiment shown in may include similar Figure 5 The ground speed PTO device shown in .

[0119] Those skilled in the art will appreciate that the shafts and gears in the above description and examples will be of any suitable material and type, and will include various peripheral components, such as support bearings and fasteners, in order to make the transmission device 10 operable.

[0120] The invention is not limited to the embodiments or examples described herein and may be modified or adapted without departing from the scope of the invention. For example, the number of selectable input stage gears and / or output stage gears in the range gearbox may be varied. Thus, as an example, the range gearbox may include three or more selectable input stage gears and / or three or more selectable output stage gears. In practice, at least for Figure 5 In the embodiment shown, the invention is not limited to use in a transmission having a range gearbox with parallel input shafts, output shafts and intermediate shafts.

Claims

1. A transmission device (10) for an agricultural vehicle, the transmission device include: A range gearbox (12) having an input shaft (26) drivably connectable to a prime mover (18) of a vehicle (1) on which the transmission arrangement is mounted, and an output shaft (28) drivably connectable to the input shaft to provide a plurality of gear ratios and operable, in use, to provide drive to at least one ground engaging member of the vehicle, the transmission arrangement further comprising an auxiliary drive shaft (14) drivably connectable to the prime mover (18) independently of the input shaft of the range gearbox, wherein the transmission arrangement comprises a torque filling drive system (16, 16', 16'', 16''') operable between the auxiliary drive shaft (14) and the output shaft (28) of the range gearbox, the torque filling drive system (16) comprising a torque filling clutch (74, 74', 74'', 74''') and configured, in use, to transfer torque from the auxiliary drive shaft (14) to the output shaft (28) of the range gearbox when the torque filling clutch is engaged; Characterized in that the torque filling drive system (16, 16', 16", 16''') is configured to engage the torque filling clutch (74, 74', 74", 74''') during a gear ratio change of the range gearbox in use to transfer torque from the auxiliary drive shaft (14) to the output shaft (28) of the range gearbox, The range gearbox (12) comprises a plurality of input stage gears (34, 36) rotatably mounted to the input shaft (26) and a first gear selection device (38) for selectively locking any one of the input stage gears to the input shaft to transmit drive between the input shaft and the selected input stage gear, a plurality of output stage gears (40, 42) rotatably mounted to the output shaft and a second gear selection device (44) for selectively locking any one of the output stage gears to the output shaft to transmit drive between the selected output stage gear and the output shaft, and an intermediate shaft (30) having a plurality of gears (46, 48, 50) for transmitting torque between the input stage gears and the output stage gears, wherein the torque filling drive system (16, 16', 16") is configured to transmit torque to the output shaft (28) of the range gearbox via the intermediate shaft (30) of the range gearbox.

2. The transmission device (10) according to claim 1, in, The input shaft (26), output shaft (28) and intermediate shaft (30) in the range gearbox (12) are arranged parallel to each other, and wherein the torque filling drive system (16, 16') includes a torque filling drive shaft (60, 60') arranged parallel to the respective shafts of the range gearbox, the torque filling drive system (16, 16') includes a torque filling drive shaft input drive device (62, 62') for transmitting drive from the auxiliary drive shaft (14) to the torque filling drive shaft (60, 60') and a torque filling drive shaft output drive device (70, 70') for transmitting drive from the torque filling drive shaft to the intermediate shaft (30) of the range gearbox, and the torque filling clutch (74, 74') forms a part of the torque filling drive shaft input drive device (62, 62') or the torque filling drive shaft output drive device (70, 70').

3. The transmission device (10) according to claim 2, in, The input shaft (26) of the range gearbox is hollow, and the auxiliary drive shaft (14) passes through the input shaft of the range gearbox, and the auxiliary drive shaft leaves the input shaft of the range gearbox at a first side of the range gearbox, and the torque filling drive shaft input drive device (62, 62') is located at the first side of the range gearbox for cooperating with the auxiliary drive shaft (14).

4. The transmission device (10) according to claim 3, in, The torque fill drive shaft output drive (70, 70') is located on an opposite side of the input stage gear (34, 36) from the torque fill drive shaft input drive (62, 62').

5. The transmission device (10) according to claim 4, in, The torque filling drive shaft output drive device (70) includes a series of meshing gears, the series of meshing gears including at least a first gear (72) mounted around the torque filling drive shaft (60) and a second gear (76) fixed to rotate with the intermediate shaft (30), and the torque filling clutch (74) is operable to selectively couple and decouple the first gear (72) from the torque filling drive shaft (60).

6. The transmission device (10) according to claim 3, in, The torque fill clutch (74') forms part of the torque fill drive shaft input drive (62').

7. The transmission device (10) according to claim 6, in, The torque filling drive shaft input drive (62') includes a series of meshing gears including at least a first gear (66') fixed for rotation with the auxiliary drive shaft (14) and another gear (64'), wherein the torque filling clutch (74') is operable to selectively couple and decouple the other gear (64') from the torque filling drive shaft (60').

8. The transmission device (10) according to claim 6 or 7, in, The torque fill drive shaft output drive (70') includes a gear (72') fixed for rotation with the torque fill drive shaft (60'), the gear (72') being in constant meshing engagement with one of the input stage gears (36) of the range gearbox, and wherein the one of the input stage gears (36) is in constant meshing engagement with a gear (48) fixed for rotation with the intermediate shaft (30) of the range gearbox.

9. The transmission device (10) according to claim 1, in, The torque filling drive system (16") includes a series of meshing gears, a first meshing gear (66") in the series of meshing gears being fixed to rotate with the auxiliary drive shaft (14), and the torque filling clutch (74") being operable to selectively couple and decouple a last gear (76") in the series of meshing gears with an intermediate shaft (30) of the range gearbox.

10. The transmission device (10) according to claim 1, in, The transmission arrangement includes a ground speed PTO transmission shaft (88) which is drivably engageable with an output shaft (28) of the range gearbox via a ground speed PTO clutch (84), and the torque fill drive system (16''') is operable to transfer torque from the auxiliary drive shaft (14) via the ground speed PTO transmission shaft (88) and the ground speed PTO clutch (84) to the output shaft (28) of the range gearbox.

11. The transmission device (10) according to claim 10, in, The torque filling drive system (16") includes a gear train (96) for transmitting drive between the auxiliary drive shaft (14) and the ground speed PTO transmission shaft (88), and the torque filling clutch (74'") is operable to drivingly couple and decouple a last gear (94) in the gear train with the ground speed PTO transmission shaft (88).

12. The transmission device (10) according to claim 11, in, The torque-filling drive system (16''') includes another clutch operable to drivingly couple a first gear (98) in the gear train (96) to the auxiliary drive shaft (14).

13. The transmission device (10) according to claim 1 or 2, in, The transmission arrangement further comprises a powershift transmission (PS) (22) located upstream of the range gearbox.

14. The transmission device (10) according to claim 1 or 2, in, The transmission device also includes a reciprocating gearbox (20) located upstream of the range gearbox.

15. An agricultural vehicle (1) comprising a transmission device (10) according to any one of claims 1 to 14.

16. An agricultural vehicle (1) according to claim 15, comprising a prime mover (18) operatively connected to an input shaft (26) of the range gearbox and to the auxiliary drive shaft (14).

17. A method of operating an agricultural vehicle (1), the agricultural vehicle being an agricultural vehicle according to claim 15 or 16, the method comprising engaging the torque fill clutch (74, 74', 74", 74''') during a range gear change to transfer torque from the auxiliary drive shaft (14) to the output shaft (28) of the range gearbox.

18. The method of claim 17, comprising disengaging the torque fill clutch (74, 74', 74", 74''') upon completion of the range shift.

19. The method according to claim 17, in, The agricultural vehicle (1) has a transmission device (10) according to any one of claims 1 to 14, and wherein the step of engaging the torque filling clutch (74, 74', 74'') to transfer torque from the auxiliary drive shaft (14) to the output shaft (28) of the range gearbox is performed during a change of an input stage range gear.

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