GB2544131A

GB2544131A - A wheel axle for a combine harvester

Info

Publication number: GB2544131A
Application number: GB1611322.7A
Authority: GB
Inventors: Ducroquet Frederic
Original assignee: AGCO Corp
Current assignee: AGCO Corp
Priority date: 2016-06-29
Filing date: 2016-06-29
Publication date: 2017-05-10
Also published as: GB201611322D0

Abstract

A wheel axle for a combine harvester is described. The wheel axle has left and right wheel suspensions which form an adjustable 4-bar linkage structure, to which can be mounted ground-contacting elements, e.g. wheels or tracks. The adjustable wheel suspension allows for the wheel axis of the axle to be adjusted in both vertical height and vertical alignment, thereby allowing the ground-contacting surface area of the wheels or tracks to be maximised for uneven terrain. The adjustable link of the wheel suspension may comprise an adjustable actuator such as a hydraulic cylinder. The combine harvester may comprise dual tyres or continuous tracks mounted on at least one wheel axle.

Description

A Wheel Axle for a Combine Harvester

Field of the Invention [0001] The present invention relates to a wheel axle for use on a combine harvester, and a harvester having such an axle.

Background of the Invention [0002] Large agricultural vehicles, such as combine harvesters, often travel over uneven or inclined terrain. To provide for improved operator comfort by reducing cab movement, as well as to minimise the effects of soil compaction, such vehicles are often provided with adjustable wheel axles which allow for independent vertical movement of the combine wheels. An example of such a system is described in European Patent Number EP 1738928 B1.

[0003] As combine harvesters increase in weight, some combines are provided with dual-tyre solutions, which act to distribute the weight of the combine over a larger ground-contact area. However, with reference to Fig. 1, such dual-tyre solutions present problems when used with the adjustable wheel axles as described above.

[0004] In Fig. 1, a cross-sectional view of a combine harvester is provided, having a known adjustable wheel axle. The main body of the combine harvester, indicated at 10, is at least partly supported by respective left and right dual tyres 12a,12b. The dual tyres 12a, 12b are connected with the combine 10 via wheel axle 14.

[0005] The wheel axle 14 comprises an axle housing 16, on which are provided respective left and right wheel suspensions 18a, 18b. The wheel suspensions 18a, 18b each comprise an upper link 20a,20b and a lower link 22a,22b, wherein first ends of each of the links 20a,20b,22a,22b are pivotally attached to the axle housing 16. The opposite ends of the links 20a,20b,22a,22b of the left and right wheel suspensions 18a,18b are pivotally attached to respective left and right wheel carriers 24a,24b. The left and right dual tyres 12a, 12b are supported on the respective left and right wheel carriers 24a,24b.

[0006] Through adjustment of appropriate shift modules (not shown) provided in the axle housing 14 and coupled with the respective lower links 22a,22b, the vertical position of the wheel carriers 24a,24b relative to the axle housing 14 can be varied. As a result, the vertical height of the axis of rotation of the left and right dual tyres 12a, 12b can be adjusted as required. Due to the increased contact width provided by dual-tyre solutions, such vertical displacement of the left and right wheel axes A and B on inclined terrain will often result in a loss of surface contact, as illustrated in Fig. 1 where an entire tyre of both left and right dual tyres 12a, 12b are not in contact with the inclined surface 26. Such reduced contact causes excessive stresses on the tyres and on the levelling system, resulting in increased likelihood of structural failure of components. In these situations, an operator is driven to revert to a single-tyre system, or to forego use of the levelling system completely.

[0007] It is an object of the invention to provide a wheel axle system more suitable for use with dual-tyre solutions.

Summary of the Invention [0008] Accordingly, there is provided a wheel axle for a combine harvester, the wheel axle comprising: an axle housing; left and right wheel suspensions provided on the axle housing; and at least one shift module in the axle housing for shifting the wheel suspensions, wherein the wheel suspensions each comprise: first and second links, and a wheel carrier, where first ends of the first and second links are pivotally mounted to the axle housing, and opposite second ends of the first and second links are pivotally mounted to the wheel carrier, the wheel carrier moveable relative to the axle housing by actuation of the at least one shift module, and characterised in that at least one of the first and second links of each of the wheel suspensions is adjustable in length to provide for adjustment of the vertical alignment of the wheel carrier relative to the axle housing.

[0009] By providing for adjustment of the vertical alignment of the wheel carriers of the axle, as a result the wheel axis of both the left and right wheel can be separately aligned with the slope of the underlying surface. The left and right wheel suspensions effectively form an adjustable 4-bar linkage structure, which allows for the wheel axis of the axle to be adjusted in both vertical height and vertical alignment, thereby allowing the groundcontacting surface area to be maximised for uneven terrain. Accordingly, wheels carried on the wheel axle can be configured to more closely follow the ground slope, thereby ensuring maximum ground-contacting surface area. While the invention is described as a wheel axle, it will be understood that the axle may be used in combination with other ground-contacting systems of a combine, e.g. continuous tracks.

[0010] Preferably, the at least one adjustable link of the wheel suspension comprises an adjustable actuator, preferably a hydraulic cylinder. The adjustable actuator is configured to adjust the length of the adjustable link.

[0011] Through appropriate regulation of hydraulic pressure in the hydraulic cylinder, the wheel suspension can be accurately controlled to adjust the vertical alignment of the wheel carrier.

[0012] Preferably, the wheel axle comprises respective left and right single-acting hydraulic cylinders as adjustable links of the respective left and right wheel suspensions, the chambers of the left and right single-acting hydraulic cylinders in fluid communication with each other.

[0013] By providing two single-acting cylinders in communication with each other as the adjustable links, accordingly the hydraulic pressure in the levelling system of the wheel axle will act to balance out between the cylinders. Accordingly, the wheel axle presents a passive levelling system, as the adjustable links extend or retract until the same load is carried by both wheel suspensions, thereby indicating a balanced and level suspension.

[0014] Preferably, the wheel axle comprises a pressure regulator valve in fluid communication with the chambers of the left and right single-acting hydraulic cylinders, wherein the pressure regulator valve is controlled by the actuation of at least one of the shift modules.

[0015] The pressure regulator valve may be connected to a supply of hydraulic fluid, wherein additional hydraulic fluid may be supplied to the chambers of the left and right single-acting hydraulic cylinders in the case of an imbalance due to actuation of the shift modules.

[0016] Preferably, the at least one shift module is provided as a piston-cylinder unit. Alternatively, the at least one shift module is provided as an electromechanical spindle drive. Preferably, the at least one shift module is coupled with at least one of the first and second links of each of the wheel suspensions.

[0017] Preferably, the first link of the wheel suspensions comprises an adjustable actuator, and the wheel axle comprises two shift modules, wherein the shift modules are each coupled to a respective one of the second links of the wheel suspensions. The shift modules are coupled to the axle housing, such that actuation of the shift modules pivots the second links relative to the axle housing.

[0018] Preferably, the wheel suspensions each form a 4-bar linkage between the links, the wheel carrier and the axle housing, wherein the first link of the wheel suspensions is provided as the upper link of the 4-bar linkage, and the second link is provided as the lower link of the 4-bar linkage.

[0019] Preferably, the wheel axle further comprises left and right adjustable extenders provided on the respective wheel carriers of the left and right wheel suspensions.

[0020] The use of adjustable extenders allows for variation of the track width for the axle.

[0021] In one embodiment, the adjustable extenders are provided as a plurality of extender pieces of different dimensions. Alternatively, the adjustable extenders are provided as an extendable body, the length of which is adjusted by an actuator, e.g. a hydraulic cylinder.

[0022] The wheel axle may be provided as a kit for installation on a new combine harvester, or retrofitting onto an existing combine.

[0023] There is further provided a combine harvester comprising at least one wheel axle as described above, and left and right ground-contacting elements provided on the at least one wheel axle.

[0024] Preferably, the wheel axle forms a passive levelling system, wherein the adjustable links of the wheel axle extend or retract until both ground-contacting elements carry the same load of the vehicle, or the adjustable link cylinder bottoms out.

[0025] Additionally or alternatively, the combine harvester comprises a controller arranged to adjust the at least one shift module and the at least one adjustable link of the wheel suspensions to maximise the ground-contacting surface area of the left and right ground-contacting elements.

[0026] Preferably, the combine harvester comprises left and right dual tyres mounted on the at least one wheel axle. Additionally or alternatively, the combine harvester comprises left and right continuous tracks mounted on the at least one wheel axle.

Brief Description of the Drawings [0027] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [0028] Fig. 1 is a cross-sectional view of a prior art combine harvester having a wheel axle levelling solution; [0029] Fig. 2 is an illustration of a wheel axle according to the invention; [0030] Fig. 3 is a first cross-sectional view of a combine harvester having a wheel axle as shown in Fig. 2, and [0031] Fig. 4 is a further cross-sectional view of a combine harvester having a wheel axle as shown in Fig. 2.

Detailed Description of the Invention [0032] With reference to Fig. 2, a wheel axle according to the invention is indicated at 28. The wheel axle 28 comprises an axle housing 30, on which are provided respective left and right wheel suspensions 32a,32b.

[0033] The wheel suspensions 32a,32b each comprise an upper link 34a,34b and a lower link 36a,36b, wherein first ends of each of the links 34a,34b,36a,36b are pivotally attached to the axle housing 30. The opposite ends of the links 34a,34b,36a,36b are pivotally attached to respective left and right wheel carriers 38a,38b. The wheel carriers 38a,38b are configured to support suitable ground-contacting elements, e.g. wheels, continuous tracks. As a result, a 4-bar linkage is effectively formed in each wheel suspension 32a,32b by the arrangement of the axle housing 30, the upper links 34a,34b, the lower links 36a,36b, and the wheel carriers 38a,38b.

[0034] The wheel axle 28 further comprises first and second shift modules 40a,40b provided in the axle housing 30. The shift modules 40a,40b comprise linearly adjustable modules, the extension of which can be regulated by a suitable suspension control system. In a preferred embodiment, the shift modules 40a,40b comprise hydraulic cylinders, the linear extension of which can be controlled by supply of hydraulic fluid to the cylinders. Alternatively, the shift modules 40a,40b may comprise electromechanical spindle drives, wherein the linear extension of the shift modules 40a,40b is controlled by operation of the electromechanical drives.

[0035] The first shift module 40a is coupled to the axle housing 30 at a first end of the shift module 40a, with the opposite end of the first shift module 40a coupled to the lower link 36a of the left wheel suspension 32a. Accordingly, adjustment of the first shift module 40a acts to raise or lower the position of the left wheel carrier 38a, by movement of the notional 4-bar linkage of the left wheel suspension 32a.

[0036] Similarly, the second shift module 40b is coupled to the axle housing 30 at a first end of the shift module 40b, with the opposite end of the second shift module 40b coupled to the lower link 36b of the left wheel suspension 32b. Accordingly, adjustment of the second shift module 40b acts to raise or lower the position of the right wheel carrier 38b, by movement of the notional 4-bar linkage of the left wheel suspension 32b.

[0037] The lower links 36a,36b are provided as links of a fixed length, while the upper links 34a,34b of the wheel suspensions 32a,32b comprise links which are adjustable in length. In the illustrated embodiment, the links 34a,34b are formed by hydraulic cylinders, preferably, single-acting cylinders, the length of which can be adjusted by supply of hydraulic fluid to the cylinders. The hydraulic fluid is supplied via a pressure regulating valve 42. The pressure regulating valve 42 is controlled to equalise the pressure between the hydraulic cylinders of the links 34a,34b and the hydraulic cylinder of one of the shift modules 40b.

[0038] In one embodiment, the pressure regulating valve 42 is coupled with a main hydraulic pump P of a vehicle to provide a supply pressure. Such a configuration provides an active control of the cylinder pressure. Alternatively, a cut-in/cut-out valve may be used in combination with a hydraulic accumulator. This allows the system pressure to be maintained between the cylinders between the cut-in pressure and the cut-out pressure of the valve.

[0039] As the adjustable links 34a,34b are connected together, the constant volume of hydraulic fluid between the two links 34a,34b will not change on flat terrain, allowing for a self-levelling of the wheel suspension. On uneven ground, the potentially different pressures experienced at the different cylinders requires a reaction in the supply level of hydraulic fluid.

[0040] While the embodiment of Fig. 2 shows the links 34a,34b provided as hydraulic cylinders, it will be understood that any other adjustable link structure may be used, e.g. an electromechanical actuator.

[0041] As the length of the upper links 34a,34b can be adjusted, accordingly the dimensions of the notional 4-bar linkages defined by the axle housing 30, the upper links 34a,34b, the lower links 36a,36b, and the wheel carriers 38a,38b can be varied. As a result, the vertical alignment of the wheel carriers 38a,38b can be adjusted relative to the axle housing 30.

[0042] While the illustrated embodiment shows the upper links 34a,34b as being adjustable in length, with the lower links 36a,36b being fixed in length and connected with the shift modules 40a,40b, it will be understood that other configuration of the elements of the wheel axle 28 may be provided. For example, in an alternative embodiment, one of the upper or lower links may be a fixed-length link, while the other of the links may be an adjustable-length link additionally connected to an end of an associated shift module.

[0043] In some embodiments, the wheel axle 28 is further provided with a controller 50 (Figs. 3 & 4). The controller 50 is arranged to adjust the operation of the wheel axle 28, in particular the control of the adjustable links 34a,34b and the shift modules 40a,40b to maintain maximum ground-contacting surface area of the wheels or tracks which are mounted on the axle 28. It will be understood that the controller 50 may be provided as a stand-alone control device, or may be provided as a programming routine for operation on a vehicle Electronic Control Unit (ECU).

[0044] In addition, the wheel axle 28 may be provided with additional sensor systems to scan the surface profile in the area ahead of the wheel axle 28, to anticipate any changes in the terrain slope in front of the wheels or tracks which are mounted on the axle 28. The output of such sensor systems can be communicated to the controller 50, such that the responsiveness of the systems of the wheel axle 28 can be improved. Such sensors may comprise ground-scanning radar, ultrasonic sensors, etc. Additionally or alternatively, the controller may be provided with recorded terrain maps, indicating a stored surface profile or elevation profile for an area in which a vehicle having the wheel axle 28 is operating.

[0045] Examples of the operation of the wheel axle 28 of the invention are provided in Figs. 3 and 4.

[0046] With reference to Fig. 3, the wheel axle 28 is shown as provided on a combine harvester, the main body of which is indicated at 44. The combine 44 is at least partly supported by respective left and right dual tyres 46a,46b. The dual tyres 46a,46b are mounted on the respective left and right wheel carriers 38a,38b of the wheel axle 28, along respective left and right wheel axes A and B. In Fig. 3, it can be seen that the wheel suspensions 32a,32b of the axle 28 have been adjusted in the vertical direction to accommodate the sloping terrain 48, to maintain the combine harvester body 44 in an upright alignment. In addition, the upper adjustable links 34a,34b of the wheel suspensions 32a,32b have adjusted in length to allow for the wheel axes A,B of the respective left and right dual tyres 46a,46b to lie substantially parallel to the underlying surface 48. In particular, the upper link 34a of the left wheel suspension 32a has retracted, to allow the left wheel carrier 38a to be tilted in an upwards direction. The upper link 34b of the right wheel suspension 32b has extended, to allow the right wheel carrier 38b to tilt in a downwards direction. As a result, the dual tyres 46a,46b are adjusted to have maximum ground-contacting surface area.

[0047] An alternative situation is illustrated in Fig. 4, which is provided with common reference numerals to Fig. 3. In Fig. 4, the underlying terrain 48 is unevenly sloped, with the result that an active control of the vertical alignment of the wheel carriers 38a,38b is required to ensure the maximum ground-contacting surface area of the dual tyres 46a,46b. In this case, it can be seen that the upper link 34a of the left wheel suspension 32a is extended to tilt the left wheel carrier 38a in a downwards direction, while the upper link 34b of the right wheel suspension 32b is also slightly extended to compensate for the sloped terrain 48. By adjusting the wheel suspensions 32a,32b in this manner, the respective wheel axes A,B are adjusted to lie substantially parallel to the slope of the underlying terrain 48.

[0048] By providing for adjustment of the vertical alignment of the wheel carriers of the axle, as a result the wheel axes of both the left and right wheel can be separately aligned with the slope of the underlying surface. Accordingly, wheels or tracks carried on the wheel axle can be configured to more closely follow the ground slope, thereby ensuring maximum ground-contacting surface area.

[0049] The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention.

Claims

1. A wheel axle for a combine harvester, the wheel axle comprising: an axle housing; left and right wheel suspensions provided on the axle housing; and at least one shift module in the axle housing for shifting the wheel suspensions, wherein the wheel suspensions each comprise: first and second links, and a wheel carrier, where first ends of the first and second links are pivotally mounted to the axle housing, and opposite second ends of the first and second links are pivotally mounted to the wheel carrier, the wheel carrier moveable relative to the axle housing by actuation of the at least one shift module, and characterised in that at least one of the first and second links of each of the wheel suspensions is adjustable in length to provide for adjustment of the vertical alignment of the wheel carrier relative to the axle housing.

2. The wheel axle of claim 1, wherein the at least one adjustable link of the wheel suspension comprises an adjustable actuator, preferably a hydraulic cylinder.

3. The wheel axle of claim 2, wherein the wheel axle comprises respective left and right single-acting hydraulic cylinders as adjustable links of the respective left and right wheel suspensions, the chambers of the left and right single-acting hydraulic cylinders in fluid communication with each other.

4. The wheel axle of claim 3, wherein the wheel axle comprises a pressure regulator valve in fluid communication with the chambers of the left and right single-acting hydraulic cylinders, wherein the pressure regulator valve is controlled by the actuation of at least one of the shift modules.

5. The wheel axle of claim 1, wherein the at least one shift module is provided as a piston-cylinder unit.

6. The wheel axle of claim 1, wherein the first link of the wheel suspensions comprises an adjustable actuator, and the wheel axle comprises two shift modules, wherein the shift modules are each coupled to a respective one of the second links of the wheel suspensions.

7. The wheel axle of claim 6, wherein the shift modules are coupled to the axle housing, such that actuation of the shift modules pivots the second links relative to the axle housing.

8. The wheel axle of claim 1, wherein the left and right wheel suspensions each form a 4-bar linkage between the links, the wheel carrier and the axle housing, wherein the first link of the wheel suspensions is provided as the upper link of the 4-bar linkage, and the second link is provided as the lower link of the 4-bar linkage.

9. The wheel axle of claim 1, wherein the wheel axle further comprises left and right adjustable extenders provided on the respective wheel carriers of the left and right wheel suspensions.

10. The wheel axle of claim 9, wherein the adjustable extenders are provided as a plurality of extender pieces of different dimensions.

11. The wheel axle of claim 9, wherein the adjustable extenders are provided as an extendable body, the length of which is adjusted by an actuator, e.g. a hydraulic cylinder.

12. A combine harvester comprising at least one wheel axle as claimed in claim 1, and left and right ground-contacting elements provided on the at least one wheel axle.

13. The combine harvester of claim 12, wherein the combine harvester comprises a controller arranged to adjust the at least one shift module and the at least one adjustable link of the wheel suspensions to maximise the ground-contacting surface area of the left and right ground-contacting elements.

14. The combine harvester of claim 12, wherein the combine harvester comprises left and right dual tyres or left and right continuous tracks mounted on the at least one wheel axle.