Self-propelled vehicles including a differential system

Patent metadata

Field	Value
Publication number	US-10953918-B2
Application number	US-201716099599-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	May 19, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

Self-propelled vehicles that include swiveling caster wheels and independent drive wheels are disclosed. The self-propelled vehicles are selectively steered in a caster wheel steering mode or a drive wheel steering mode. The vehicle includes a differential system that may include a differential valve that allows hydraulic fluid to be transferred between the left and right drive systems. The differential system may be operable during the caster wheel steering mode such as when the vehicle is driven for transport between sites.

First claim

What is claimed is:

1. A self-propelled vehicle comprising:
a chassis;
first and second drive wheels connected to the chassis;
first and second drive systems connected to the first and second drive wheels for independently controlling a rotational drive speed of each of the first and second drive wheels;
caster wheels connected to the chassis;
a steering system selectively operable between a drive wheel steering mode and a caster wheel steering mode, wherein, in the caster wheel steering mode, the steering system controls a swivel position of the caster wheels to steer the vehicle and the first and second drive systems are controlled equally, and, in the drive wheel steering mode, the steering system controls the speed difference between the first and second drive wheels to steer the vehicle; and
a differential system connected to the drive systems of the first and second drive wheels to enable the first and second drive wheels to operate at different speeds to follow an arc defined by the swivel position of the caster wheels during steering of the vehicle in the caster wheel steering mode.

2. The self-propelled vehicle as set forth in claim 1 wherein the differential system comprises a differential valve connected to the drive systems of the first and second drive wheels to enable the first and second drive wheels to operate at different speeds in the caster wheel steering mode.

3. The self-propelled vehicle as set forth in claim 1 , wherein, in the drive wheel steering mode, the caster wheels are free to pivot with respect to the chassis in response to differences in the first drive wheel speed and the second drive wheel speed.

4. The self-propelled vehicle as set forth in claim 1 , wherein, in the caster wheel steering mode, the caster wheels are connected to the steering system and are controlled by the steering system.

5. The self-propelled vehicle as set forth in claim 1 , wherein the first drive system includes a first motor and a first pump connected to the first motor to provide fluid to the first motor, and the second drive system includes a second motor and a second pump connected to the second motor to provide fluid to the second motor, wherein the first pump provides a first fluid flow to the first motor and the second pump provides a second fluid flow to the second motor.

6. The self-propelled vehicle as set forth in claim 5 wherein the first motor is connected to the first drive wheel to rotate the first drive wheel and the second motor is connected to the second drive wheel to rotate the second drive wheel, the first and second pumps being powered by an engine, the engine being supported by the chassis.

7. The self-propelled vehicle as set forth in claim 6 , wherein the steering system controls the speed difference between the first and second drive wheels by varying the first and second fluid flows in the drive wheel steering mode.

8. The self-propelled vehicle as set forth in claim 6 , wherein the first pump and second pump are powered equally in the caster wheel steering mode, the differential valve adjusting the fluid flow between the first and second drive systems to enable the first and second drive wheels to rotate at different speeds.

9. The self-propelled vehicle as set forth in claim 1 , wherein the first and second drive wheels can be driven in different directions when the vehicle is in the drive wheel steering mode and are prevented from rotating in different directions when the vehicle is in the caster wheel steering mode.

10. The self-propelled vehicle as set forth in claim 1 further comprising a control system to selectively operate the steering system in the drive wheel steering mode or the caster wheel steering mode.

11. The self-propelled vehicle as set forth in claim 1 wherein the steering system comprises a steering cylinder for pivoting the caster wheel in the caster wheel steering mode.

12. The self-propelled vehicle as set forth claim 11 wherein the steering system comprises a tie-rod, the tie-rod being locked in position in the caster wheel steering mode and being variable in length in the drive wheel steering mode.

13. The self-propelled vehicle as set forth in claim 12 wherein the tie-rod comprises a disengagement cylinder, the disengagement cylinder being in a fixed position in the caster wheel steering mode and floats in the drive wheel steering mode.

14. The self-propelled vehicle as set forth in claim 1 further comprising an agricultural device supported by the chassis, the agricultural device being selected from the group consisting of a baler, cutting or mower head, sickle bar, spray tank, spray boom, harvesting devices and broadcast spreader.

15. A self-propelled vehicle comprising:
a chassis;
first and second drive wheels connected to the chassis;
first and second drive systems connected to the first and second drive wheels, each of the first and second drive systems including a pump and a motor;
a caster wheel connected to the chassis;
a steering system connected to the caster wheel; and
a differential valve connected to the motors of the first and second drive systems, the differential valve selectively transferring fluid between the motors to enable the motors to rotate the first and second wheels at different speeds.

16. The self-propelled vehicle as set forth in claim 15 wherein each of the first and second drive systems comprise separate fluid lines connecting the pump and the motor, the differential valve connecting the fluid lines of the first and second drive systems.

17. The self-propelled vehicle as set forth in claim 15 comprising a steering system that selectively controls a swivel position of the caster wheel to steer the vehicle.

18. The self-propelled vehicle as set forth in claim 17 wherein the steering system comprises a steering cylinder for controlling the swivel position of the caster wheel.

19. The self-propelled vehicle as set forth in claim 18 wherein the steering system comprises a tie-rod, the tie-rod being locked in position in the caster wheel steering mode and being variable in length in the drive wheel steering mode.

20. The self-propelled vehicle as set forth in claim 19 wherein the tie-rod comprises a disengagement cylinder, the disengagement cylinder being in a fixed position in the caster wheel steering mode and floating in the drive wheel steering mode.

Assignees

• Vermeer Mfg Co

Inventors

• Graham Curt T
• Dockter Nathan D
• Recker Kent M
• Burns Gary J
• Thompson Kent L
• Rempe Scott A
• Knapp Jeffrey T

Classifications

• A01B69/007

  Steering or guiding of agricultural vehicles, e.g. steering of the tractor to keep the plough in the furrow · CPC title

• B62D11/24

  Endless track steering specially adapted for vehicles having both steerable wheels and endless track · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• B62D11/02 Primary

  by differentially driving ground-engaging elements on opposite vehicle sides · CPC title

• B60B33/026

  being actuated remotely, e.g. by cable or electrically · CPC title