GB2475227A - Drive system for self-propelled application machine - Google Patents

Abstract

A drive system for a self-propelled agricultural application machine (10 see fig 1) is provided. The drive system comprises an engine 24 which is drivingly connected to a transmission unit 26 by a single driveshaft 28 so that the rotational output of the engine is axially aligned with the rotational input to the transmission thus minimising power loss. The drive system further comprises a power takeoff gearbox 30 through which the driveshaft passes, wherein the power takeoff gearbox has an output 355 which is driven by the driveshaft. The output may be used to drive a hydraulic pump 41 and/or a power takeoff shaft for driving auxiliary equipment such as spraying apparatus.

Description

DESCRIPTION

DRIVE SYSTEM FOR A SELF-PROPELLED APPLICATION MACHINE

The invention relates to self-propelled agricultural application machines and particularly to drive systems for such.

Self-propelled agricultural application machines such as fertilizer/chemical spreaders and sprayers, manure spreaders and soil injection machines are used by farmers and contractors to apply various materials to fields of crops. The vehicles typically comprise a chassis and a plurality of wheels which may be narrow or wide depending on the application in hand. For example, machines which strive to minimize soil compaction may employ wide, flotation, tyres whereas sprayers that aim to minimize crop damage use narrow tyres.

The machine is typically powered by an internal combustion engine which is drivingly connected to a transmission unit. The output side of the transmission is drivingly connected to wheels of the vehicle to provide a propulsion force. In addition, the transmission typically powers at least one power takeoff shaft to drive a hydraulic pump or mechanically driven auxiliary equipment. A pump driven thereby serves to apply pressurised fluid for various on-board vehicle fttnctions such as steering, brakes and spraying/spreading/injection apparatus.

The latter may serve to deliver material from a storage tank to the ground or crop. Depending on the size and type of the application machine the application apparatus, especially spreading apparatus which are required to spread high volumes of solid material onto the ground via centrifugal spreaders, demands a significant proportion of the engine's power.

In addition to hydraulic pumps the transmission may also comprise an auxiliary mechanical power takeoff shaft which can be employed to drive tillage equipment attached to the rear of the vehicle. Again, such equipment can demand a significant proportion of the engine's power.

As application machines increase in size to meet the demands of customers then the machine manufacturers must increase the engine and transmission size to meet the power requirements. Any increase in the size of the engine and transmission leads to an increase in overall weight and thus potential soil compaction and/or tyre width required.

It is thus an object of the invention to provide an improved drive system for a self-propelled agricultural application machine which alleviates the above-mentioned problems associated with increasing engine and transmission size.

In accordance with the invention there is provided a drive system for a self-propelled agricultural application machine, the drive system comprising an engine which is drivingly connected to a transmission by a single driveshaft so that the rotational output of the engine is axially aligned with the rotational input to the transmission, the drive system further comprising a power takeoff (PTO) gearbox through which the driveshaft passes, wherein the PTO gearbox has an output which is driven by the driveshaft.

By placing a PTO gearbox between the engine and transmission, the latter need not increase in size to cater for the increase in power demand from auxiliary equipment. By tapping off' the power for the auxiliary systems upstream of the transmission, all power from the transmission is available for propulsion of the vehicle.

With appropriate engine management therefore, an engine having a maximum power output which is significantly greater than the maximum permitted power of the transmission unit may be used.

Furthermore, the axial alignment of the engine output and transmission input provides a robust torque transfer therebetween without any power loss through intermediate gearing.

In the case of the PTO gearbox driving a hydraulic pump, the supply of pressurised fluid may be used to power material application apparatus attached to the application machine.

Alternatively, or in addition to, the pressurised fluid may be used for vehicle control systems such as brakes and steering.

The PTO gearbox may drive a mechanical PTO shaft which may be used to power application equipment or tillage equipment attached to the machine.

As mentioned above, appropriate engine management is preferably used to prevent excessive torque being delivered to the transmission thus minimizing the rise of damage. Preferably the transmission is dedicated to transmit power solely to a vehicle propulsion system.

In a preferred embodiment the transmission is a continuously variable transmission which is operable in a continuous range of input-to-output drive ratios. Alternatively, the transmission may be a stepped ratio transmission.

The PTO gearbox preferably includes an output side flange which comprises a first aperture through which the drive shaft passes, and a second aperture which is redundant and blanked and is suitable for receiving an output drive shaft in a different configuration.

Advantageously, this permits a manufacturer to use a common flange for the PTO gear box which can be employed for more than one configuration. This not only delivers simplicity in assembly but provides a significant cost saving.

The PTO gearbox may also include an input side flange which comprises a first aperture through which the drive shaft passes and a second aperture through which a driving connection passes between the PTO gearbox and a hydraulic pump.

Further advantages of the invention will become apparent from the following description of specific embodiments with reference to the appended drawings in which:-Figure 1 is a perspective view of a self-propelled agricultural application machine which includes a drive system in accordance with an embodiment of the present invention; Figure 2 is a side view of the application machine of Figure 1; Figure 3 is a side view of the drive system included in the application machine of Figure 1; Figure 4 is rear view of the output side flange of the PTO gearbox included in the drive system of Figure 3; Figure 5 is a front view of the input side flange of the PTO gearbox included in the drive system of Figure 3; Figure 6A is a side view of the PTO gearbox of the drive system of Figure 3; Figure 6B is a sectional view through the PTO gearbox of the drive system of Figure 3; Figure 7 is side view of a self-propelled agricultural application machine Figure 8 is a side view of a drive system included in the application machine of Figure 7; Figure 9 is a rear view of a PTO gearbox included in the drive system of Figure 8; Figure 10 is a front view of the PTO gearbox of Figure 9; Figure hA is a side view of the PTO gearbox of Figure 9; Figure 1 lB is a sectional view through the PTO gearbox of Figure 9; Figure 12 is a schematic view of the drive system of Figure 3; and, Figure 13 is a schematic view of the drive system of Figure 8.

With reference to Figures 1 and 2 a self-propelled agricultural application machine 10 includes a chassis 12 having mounted thereto two rear tyres 14 and a single front wheel 16 which is positioned transversely centrally. All wheels 14,16 have floatation tyres which minimize soil compaction when driven across a field.

The application machine 10 further comprises a driver's cab 18 and a storage tank 20 which stores the material to be applied to the field. The storage tank 20 may take many different forms depending upon the material, or materials, to be applied. For example the tank shown includes three separate compartments 20a,20b,20c for the storage of different granular fertilizer which is applied to the field in varying ratios using a spreader disc 22. However, it should be appreciated that the storage tank may comprise only a single compartment and may alternatively be used for liquid such as liquid fertilizer or slurry.

An engine 24 is positioned at least partly under the cab 18 and covered by a hood 25. The engine 24 is drivingly connected to a transmission unit 26, which is located behind or under the cab, by a single drive shaft 28. The transmission unit 26 is a continuously variable transmission which is operable within a continuous range of input-to-output drive ratios.

Alternatively, the transmission unit 26 may be a stepped ratio transmission.

With reference also to Figure 12, the output from transmission 26 is drivingly connected by shaft 290 to a rear axle 29 which includes a differential and final drive which delivers power to the rear wheels 14 for propulsion of the vehicle.

The drive shaft 28 passes through a PTO gearbox 30 which is, in this example, secured to the rear side of the engine 24. The rotational output from the engine 24 is in axial alignment with the rotational input to the transmission 26 which, advantageously, minimizes power loss between the engine 24 and transmission 26 thus ensuring a robust transmission of torque.

With reference to Figures 4, 5 and 6, the PTO gearbox 30 includes an input side flange 31 and an output side flange 32 which mate with one another to provide an enclosed volume (or housing) for a plurality of gears. The two flanges 31, 32 are bolted together. On the inner surface of each flange 31,32 a plurality of supporting recesses are provided for receiving bearings associated with the gears. The recesses are cast into the structure of the flanges 311, 32.

With particular reference to Figure 6B, the input side flange 311 comprises a recess 331 which holds a bearing 332. Similarly, the output side flange 32 comprises an equivalent recess 333 which holds a bearing 334. Bearings 332, 334 support driveshaft 28 which drives a first gear 33 keyed therewith.

An intermediate second gear 34 is meshed with drive gear 33 and is supported by a short shaft 345 which rotates within associated bearings 342, 344 which are held within respective recesses 341, 343 in the flanges 31, 32. The second gear 34 is further meshed with and drives a third gear 35 and a fourth gear (not shown) which are both supported for rotational movements by associated bearings in a similar manner to the second gear 34. The third gear is keyed onto shaft 355 and the fourth gear (not shown) is keyed onto shaft 365.

Each of said shafts 355, 365 exit the PTO gearbox 30 via the input side flange 31 as shown in Figure 5 and 6B and each drive a respective hydraulic pump 41. It will be appreciated that only one hydraulic pump 41 can be seen in Figure 3 and that both pumps 41 are represented as one in the schematic view of Figure 12. Many alternative arrangements of hydraulic pump are possible including one, two, three or more pumps secured to the input or output side flange 31, 32, Each hydraulic pump 41 supplies pressurised fluid to various auxiliary functions of the application machine. In this example, these functions include a brake system 42, a steering system 43, and an auxiliary system 44 to drive hydraulic consumers associated with material application apparatus either directly associated with the application machine 10 or attached to the rear thereof.

In accordance with the invention output power from the engine 24 is tapped off by PTO gearbox 30 and employed to drive hydraulic pumps 41. Advantageously, the power required to drive these auxiliary functions is not transmitted through the transmission unit 26. This allows the maximum power rating of the engine to be significantly higher than that of the transmission 26.

Electronic control unit (ECU) 100 controls the output power of the engine 24, the input-to-output ratio of the transmission unit 26, and the switching of the auxiliary systems 44 which exploit the power taken off by PTO gearbox 30. The ECU 100 controls the engine 24 so that the power transmitted to the transmission unit 26 does not exceed a safe operating power so as to prevent damage.

Turning back to the construction of PTO gearbox 30, the flanges 31, 32 each comprise two redundant recesses 371, 373, 381, 383 which serve to receive bearings for supporting gears in an alternative configuration to be described below.

Each of the recesses, 343, 353, 363 (not visible from Fig. 6B), 373, 383 cast into the output side flange 32, and not having a shaft passing there through, have a respective cover plate 346, 356, 366, 376, 386 for preventing the ingress of dirt and for providing access to the bearings for maintenance.

The described embodiment includes two hydraulic pumps 41 mounted on the input side flange 31. However, in an alternative arrangement, more hydraulic pumps may be mounted on the output side flange 32 and driven by shafts 355, 365 and omitting the blanking plates 356, 366. In fact, it should be appreciated that any number of hydraulic pumps may be mounted to the available positions on either side of the PTO gearbox 30 to suit the given application.

Although not shown in the drawings, a mechanical drive may be taken from an output shaft of the PTO gearbox 30 to be drivingly connected to auxiliary equipment such as application apparatus or tillage equipment for example. By appropriate arrangement of the recesses and associated gears the PTO gearbox 30 can be easily tailored to the required application.

With reference to Figure 7, an alternative form of self-propelled agricultural application machine 50 is shown. The machine 50 comprises a chassis 52, a pair of rear wheels 54, a pair of front wheels 56 and a driver's cab 58. In a similar manner to the first described application machine 10, the machine 50 comprises a storage tank 60 mounted on top of the chassis 52.

However, in this example, the application machine 50 comprises a pair of front wheels and the chassis 52 is articulated at an articulation joint 62.

With reference also to Figure 8, an engine 24 is positioned under the hood 65 in a similar manner to the first described embodiment. However, in this example, a transmission unit 26 is mounted above a front axle 66 to which the front wheels 56 are attached. The engine 24 is drivingly connected to the transmission unit 26 via a PTO gearbox 30 which is of the same construction to that described above, albeit configured differently.

The output of engine 24 is drivingly connected to the PTO gearbox 30 by a first drive shaft 67 which drives first gear 33. First driveshaft 67 does not exit the PTO gearbox 30 on the output side. Therefore, a blanking plate 336 is provided on the output side flange 32.

The arrangement of gears 34, 35, associated bearings and the hydraulic pumps 41 is the same as for the embodiment shown in Figures 1 to 6.

In the configuration shown in Figures 9, 10 and 11, the PTO gearbox 30 includes further gears 37, 38 for vertically displacing the drive to the transmission unit 26. Recesses 371, 373 each hold in place a respective bearing 372, 374 for supporting gear 37 for rotational movement.

Gear 37 is meshed between driving gear 33 and driven gear 38. Recesses 381, 383 each hold in place a respective bearing 382, 384 for supporting gear 38 for rotational movement.

Blanking plate 386 is omitted from this configuration to allow a second drive shaft 68 to exit the PTO gearbox 30 driven by gear 38.

Blanking plate 366 is also omitted in this example to accommodate an internal lubrication pump 80 which is driven by shaft 355 and serves to pump oil from the bottom of PTO gearbox 30 to the top by pipes 81, 82. The pumped oil serves to lubricate bearings 382, 384, 372, 374 associated with gears 37, 38.

The vertical displacement between the output of engine 24 and the input of transmission unit 26 allows the latter to be conveniently mounted above axle 66. The output of transmission unit 26 is drivingly connected to both the front and rear wheels 56,54 via a drop box 70 which includes a plurality of meshed gears 71, 72, 73 serving to align the output thereof with the differentials 79, 29 associated with the front and rear axles respectively. Drive to the rear axle is conveyed across the articulation joint 62 by a sliding carden shaft (not shown). Drive to the front axle conveyed by a disconnect mechanism (not shown) which allows drive to the front axle to be selectively discoimected when driven on the highway for example.

In a similar vein to the first described embodiment, hydraulic pumps 41 are connected to and driven by the PTO gearbox 30. The hydraulic pumps 41 supply pressurised fluid to on-board systems such as steering and brake hydraulic systems 42, 43, and to auxiliary consumers (designated generally by 44) associated with material application equipment and tillage equipment for example.

It will be appreciated that the PTO gearbox 30 can be employed for either configuration as shown in Figures 3 and 8. The provision of a universal output side flange 32 caters for the transmission unit 26 to be driven at alternative heights allowing for the same transmission unit 26 to be installed in a three-, five-(with two rear driven axles) or four-wheel application machine. In the latter case the transmission unit 26 is mounted above the front axle 66 and thus the PTO gearbox 30 provides a vertical displacement of the drive line between engine 24 and transmission unit 26.

Conversely, in the three-wheel (or five-wheel) arrangement, the PTO gearbox 30 permits a direct through drive between the engine output and transmission input which minimizes power loss. In both cases the flanges 31 and 32 for the PTO gearbox 30 are the same.

However different permutations of the available apertures and shaft support points are employed for the two different configurations. Also, the universal flanges 31,32 allow for various different arrangements of hydraulic pumps to be mounted thereto, and driven thereby, depending on the vehicle requirements.

From reading the present disclosure, other modification will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the field of agricultural application machines and component parts therefore and which may be used instead of or in addition to features already described herein.

Claims (9)

1. CLAIMSI. A drive system for a self-propelled agricultural application machine, the drive system comprising an engine which is drivingly connected to a transmission by a single driveshaft so that the rotational output of the engine is axially aligned with the rotational input to the transmission, the drive system further comprising a power takeoff gearbox through which the driveshaft passes, wherein the power takeoff gearbox has an output which is driven by the driveshaft.
2. 2. A drive system according to Claim 1, wherein the output of the power takeoff gearbox drives at least one hydraulic pump which provides a supply of pressurised fluid.
3. 3. A drive system according to Claim 2, wherein the supply of pressurised fluid is used to power material application apparatus aftached to an application machine.
4. 4. A drive system according to any preceding claim, wherein the maximum power output of the engine exceeds a maximum permitted power input to the transmission.
5. 5. A drive system according to any preceding claim, wherein the transmission is dedicated to transmit power solely to a vehicle propulsion system.
6. 6. A drive system according to any preceding claim, wherein the transmission is a continuously variable transmission which is operable within a continuous range of input to output drive ratios.
7. 7. A drive system according to any preceding claim, wherein the power takeoff gearbox includes an output side flange which comprises a first gear support recess which supports a first gear driven by the driveshaft and a second gear support recess which is redundant and is suitable for supporting a second gear in a different configuration.
8. 8. A drive system according to any preceding claim, wherein the power takeoff gearbox includes an input side flange which comprises a first aperture through which the driveshaft passes and a second aperture through which a driving connection passes between the power takeoff gearbox and a hydraulic pump.
9. 9. A self-propelled agricultural application machine comprising a drive system according to any preceding claim.