Charge pressure circuit arrangement for steering control for a vehicle

Patent metadata

Field	Value
Publication number	US-9421999-B2
Application number	US-201414455734-A
Country	US
Kind code	B2
Filing date	Aug 8, 2014
Priority date	Aug 8, 2014
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

A steering system is described for a vehicle having steerable wheels. A hydraulic charge pressure circuit may be configured to provide charge pressure to one or more hydraulic components of the vehicle, and a hydraulic drive pressure circuit may be configured to provide working pressure to one or more other hydraulic components of the vehicle. Hydraulic machines may rotate front wheels in order to drive the vehicle, and a front valve assembly may control steering of the front wheels by controlling the hydraulic machines. The hydraulic machines may be driven to rotate the front wheels by the working pressure from the hydraulic drive pressure circuit, and the front valve assembly may control the front hydraulic machines to steer the agricultural vehicle by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly.

First claim

What is claimed is:

1. A steering system for an agricultural vehicle having one or more steerable front wheels and one or more steerable rear wheels, the steering system comprising:
a hydraulic charge pressure circuit configured to provide charge pressure to one or more hydraulic components of the agricultural vehicle;
a hydraulic drive pressure circuit configured to provide a working pressure to one or more other hydraulic components of the agricultural vehicle;
at least one front hydraulic machine configured to rotate at least one of the one or more steerable front wheels in order to drive the agricultural vehicle; and
a front valve assembly configured to control steering of the at least one steerable front wheel by controlling the at least one front hydraulic machine;
wherein the at least one front hydraulic machine is driven to rotate the at least one steerable front wheel by the working pressure from the hydraulic drive pressure circuit; and
wherein, to steer the agricultural vehicle, the front valve assembly controls the at least one front hydraulic machine by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly.

2. The steering system of claim 1 , wherein the front valve assembly is not in hydraulic communication with the hydraulic drive pressure circuit.

3. A steering system for an agricultural vehicle having one or more steerable front wheels and one or more steerable rear wheels, the steering system comprising:
a hydraulic charge pressure circuit configured to provide charge pressure to one or more hydraulic components of the agricultural vehicle;
a hydraulic drive pressure circuit configured to provide a working pressure to one or more other hydraulic components of the agricultural vehicle;
at least one front hydraulic machine configured to rotate at least one of the one or more steerable front wheels in order to drive the agricultural vehicle;
a front valve assembly configured to control steering of the at least one steerable front wheel by controlling the at least one front hydraulic machine;
a rear steering device configured to steer at least one of the one or more steerable rear wheels;
a rear valve assembly configured to control the steering of the at least one steerable rear wheel by controlling the rear steering device; and
a hydraulic steering pressure circuit configured to provide steering pressure to the rear steering device via the rear valve assembly, in order to operate the rear steering device;
wherein the at least one front hydraulic machine is driven to rotate the at least one steerable front wheel by the working pressure from the hydraulic drive pressure circuit;
wherein, to steer the agricultural vehicle, the front valve assembly controls the at least one front hydraulic machine by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly; and
wherein the rear valve assembly controls the rear steering device by controlling flow of hydraulic fluid from the hydraulic steering pressure circuit through the rear valve assembly.

4. The steering system of claim 3 , wherein the hydraulic steering pressure circuit is not in hydraulic communication with the hydraulic drive pressure circuit or the hydraulic charge pressure circuit.

5. The steering system of claim 3 , wherein the rear valve assembly includes a blocker valve configured to selectively disable the rear valve assembly, a first pilot valve configured to operate the blocker valve, at least one control valve, and a second pilot valve configured to operate the at least one control valve;
wherein the hydraulic steering pressure circuit provides steering pressure to the rear steering device via the blocker valve and the at least one control valve; and
wherein the hydraulic charge pressure circuit provides charge pressure to the first and second pilot valves to operate the first and second pilot valves and thereby control flow of hydraulic fluid from the hydraulic steering pressure circuit through the blocker valve and the at least one control valve.

6. The steering system of claim 5 , wherein the rear steering device includes a double-acting piston coupled to the at least one steerable rear wheel; and
wherein the double-acting piston is configured to receive the flow of hydraulic fluid from the hydraulic steering pressure circuit through the blocker valve and the at least one control valve in order to steer the at least one steerable rear wheel.

7. The steering system of claim 3 , wherein a steering pump for pressurizing the hydraulic steering pressure circuit is configured to provide steering pressure of between approximately 1200 and 3600 pounds per square inch.

8. The steering system of claim 1 , further including a rear steering device configured to steer at least one of the one or more steerable rear wheels.

9. The steering system of claim 8 , further including:
a rear valve assembly configured to control the steering of the at least one steerable rear wheel by controlling the rear steering device; and
a hydraulic steering pressure circuit configured to provide steering pressure to the rear steering device via the rear valve assembly, in order to operate the rear steering device;
wherein the rear valve assembly controls the rear steering device by controlling flow of hydraulic fluid from the hydraulic steering pressure circuit through the rear valve assembly.

10. A steering system for an agricultural vehicle having one or more steerable front wheels and one or more steerable rear wheels, the steering system comprising:
a hydraulic charge pressure circuit configured to provide charge pressure to one or more hydraulic components of the agricultural vehicle;
a hydraulic drive pressure circuit configured to provide a working pressure to one or more other hydraulic components of the agricultural vehicle;
at least one front hydraulic machine configured to rotate at least one of the one or more steerable front wheels in order to drive the agricultural vehicle; and
a front valve assembly configured to control steering of the at least one steerable front wheel by controlling the at least one front hydraulic machine;
wherein the at least one front hydraulic machine is driven to rotate the at least one steerable front wheel by the working pressure from the hydraulic drive pressure circuit;
wherein, to steer the agricultural vehicle, the front valve assembly controls the at least one front hydraulic machine by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the front valve assembly;
wherein front valve assembly includes a blocker valve configured to selectively disable the front valve assembly, a first pilot valve configured to operate the blocker valve, at least one control valve, and a second pilot valve configured to operate the at least one control valve;
wherein the front valve assembly controls the at least one front hydraulic machine by controlling flow of hydraulic fluid from the hydraulic charge pressure circuit through the blocker valve and the at least one control valve; and
wherein the first and second pilot valves, respectively, use the charge pressure from the hydraulic charge pressure circuit to in order to control the flow from the hydraulic charge pressure circuit through the blocker valve and the at least one control valve.

11. The steering system of claim 10 , wherein the at least one front hydraulic machine is configured to rotate the at least one steerable front wheel at a rotational speed that depends, at least in part, upon the flow of hydraulic fluid from the hydraulic charge pressure circuit through the blocker valve and th

Assignees

• Deere & Co

Inventors

• Rotole David V
• Bebernes Thomas D
• Nichols Thomas A
• Teach Kyle R

Classifications

• B62D11/005

  Hydraulic control systems · CPC title

• B62D1/22

  Alternative steering-control elements, e.g. for teaching purposes · CPC title

• B62D11/04

  by means of separate power sources · CPC title

• B62D5/09 Primary

  characterised by means for actuating valves · CPC title

• B62D11/24

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