STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

REFERENCE TO A “SEQUENCE LISTING”, A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISC AND AN INCORPORATION-BY-REFERENCE OF THE MATERIAL ON THE COMPACT DISC

None.

FIELD OF THE INVENTION

Agricultural machines, such as self-propelled sprayers and fertilizer spreaders, may have fixed wheel track axles or optional variable wheel track axles. In a fixed wheel track machine, the wheel track is determined by the overall width of the axle and the offset of the wheel. The axle is fixed and cannot extend or retract. In a variable wheel track machine, the wheel track can be adjusted to a finite wheel track limited by a minimum and maximum.

Variable wheel track offers a substantial advantage over fixed wheel track. In general, the spacing between crop rows is diverse depending on the type of crop, soil conditions, implements used to plant the crop, or planting practices of the farmer. The conditions explained limit the productivity of a fixed wheel track machine. The wheel track can be changed on a fixed wheel track; however, adjustments are labor intensive as the wheel offset must change or wheel spacers added. In the conditions described, a variable wheel track is advantageous as the wheel track can be conveniently adjusted from inside the operator cabin. The minimum and maximum limits of the variable axle are typically designed to accommodate all variants of crop spacing. Therefore, it is preferable for agricultural machines to have variable wheel track to efficiently adapt to the variations of crop row spacing. Current variable wheel track designs do have limitations. For example, when trying to adjust wheel track, especially on a high-friction surface, it is advised to operate the machine in a series of S-pattern maneuvers to assist the hydraulic cylinders in either extension or retraction. This process requires a large area to operate the machine. Additionally, a negative force is generated on the side of the machine that is turning in when extending, and the side of the machine turning out when retracting. This adds stress to the axle and wheel components and potentially leads to premature failure, and it is difficult to find large areas to complete a wheel track adjustment without disturbing crops. Also, this method of wheel track adjustment results in premature tire wear due to the uncharacteristic movement when pushing the tire away from the machine during extension or pulling the tire towards the machine when retracting. To have an agricultural vehicle with the advantages of a variable wheel track that could perform adjustments effortlessly and without the need for a large area would be a valuable technical advance in the industry.

SUMMARY OF THE INVENTION

The inventive subject matter includes: a system to simultaneously adjust a wheel track axle and a steering angle of an agricultural vehicle made of: an at least two variable wheel track axle assemblies, each one of the variable wheel track axle assemblies connected to a wheel set of the agricultural vehicle, wherein each of the variable wheel track axle assemblies is made of: an outer axle housing having disposed therein an outer axle shaft; an inner axle housing having disposed therein an inner axle shaft, wherein the inner axle housing is fixed to a center differential gear unit and the outer axle housing is fixed to a planetary gear wheel unit, wherein the outer axle housing slidably connects the inner axle housing by means of a track width control hydraulic cylinder connected between the center differential gear unit and the outer axle housing, the outer axle being splinedly connected to the inner axle, wherein the outer axle is configured to move axially within the inner axle spline to maintain wheel control: a hydraulic steering cylinder connected to the planetary gear wheel unit of each wheel to independently adjust the steering angle of a wheel in a wheel set; a linear position sensor configured to detect the position of a wheel in a wheel set; and a computer system made of a controller and microprocessor and a non-transitory computer-readable storage medium coupled to the microprocessor, wherein the non-transitory computer-readable storage medium is encoded with computer-readable instructions; wherein when the computer-readable instructions are executed, the microprocessor performs the respective functions, wherein the computer system is configured to input a desired set point; an input of the wheel position from the position sensor and a signal to the track width adjustment cylinders to control the length of the wheel track axle and an output signal to the hydraulic steering cylinder to independently adjust the steering angle of each wheel in a wheel set.

The inventive subject matter further includes: a method for varying wheel track axle in an agricultural vehicle in operation with independent wheel angle control including the steps of: adjusting the track width from about 114 to 144 inches of a wheel sets while the agricultural vehicle is moving: adjusting the wheel angle to extend outwardly up to 3 degrees when the track is extending outwardly; adjusting the wheel angle to extend inwardly up to 3 degrees when the track is extending inwardly; and adjusting the wheel angle to zero when the track is stationary.

