Steering arrangement

Patent metadata

Field	Value
Publication number	US-9744986-B2
Application number	US-201414333312-A
Country	US
Kind code	B2
Filing date	Jul 16, 2014
Priority date	Jul 22, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A steering arrangement including a first, second, third and fourth hydraulic chamber, the first and third chambers being operable to steer in a first direction and the second and fourth chambers being operable to steer in a second direction. A pump system supplies fluid to a steering system, which is operable to supply the pressurized fluid to one or more of the first, second, third and fourth hydraulic chambers. The steering system having a first mode wherein fluid is supplied to the first and third hydraulic chambers to steer in the first direction, or pressurized fluid is supplied to the second and fourth hydraulic chambers to steer in the second direction. The steering system having a second mode to steer in the first direction, or to steer in the second direction, such that the steering ratio is higher in the second mode than in the first mode.

First claim

The invention claimed is:

1. A steering arrangement including a first hydraulic pressure chamber, a second hydraulic pressure chamber, a third hydraulic pressure chamber and a fourth hydraulic pressure chamber, the first and third pressure chambers being selectively operable to steer in a first direction and the second and fourth pressure chambers being selectively operable to steer in a second direction,
a pump system for supplying pressurised fluid to a steering system,
the steering system being operable to supply the pressurised fluid to one or more of the first, second, third and fourth hydraulic pressure chambers,
the steering system having a first mode wherein pressurised fluid is simultaneously supplied to the first and third hydraulic pressure chambers to steer in the first direction or wherein pressurised fluid is simultaneously supplied to the second and fourth hydraulic pressure chambers to steer in the second direction,
the steering system having a second mode wherein pressurised fluid is supplied to one of the first and third hydraulic pressure chambers to steer in the first direction or wherein pressurised fluid is supplied to one of the second and fourth hydraulic pressure chambers to steer in the second direction,
such that the steering ratio is higher in the second mode than in the first mode.

2. A steering arrangement as defined in claim 1 wherein with the steering system in the second mode, pressurised fluid is supplied only to one of the first and third hydraulic pressure chambers to steer in the first direction or pressurised fluid is supplied only to one of the second and fourth hydraulic pressure chambers to steer in the second direction.

3. A steering system as defined in claim 1 including:
a first steering unit,
a second steering unit,
wherein with the steering system in the first mode:
the first steering unit selectively supplies pressurised fluid to one of the first or third chamber simultaneously with the second steering unit supplying pressurised fluid to the other of the first or third chamber to steer in the first direction, or
the first steering unit selectively supplies pressurised fluid to one of the second or fourth chamber simultaneously with the second steering unit supplying pressurised fluid to the other of the second or fourth chamber to steer in the second direction.

4. A steering arrangement as defined in claim 3 in which with the steering system in the second mode the first steering unit selectively supplies pressurised fluid to one of the first and third hydraulic pressure chambers simultaneously with the second steering unit supplying pressurised fluid to said one of the first and third hydraulic pressure chambers to steer in the first direction, or
the first steering unit selectively supplies pressurised fluid to one of the second and fourth hydraulic pressure chambers simultaneously with the second steering unit supplying pressurised fluid to said one of the second and fourth hydraulic pressure chambers to steer in the second direction.

5. A steering arrangement as defined in claim 4 including a valve having a first position which defines the first mode and a second position which defines the second mode.

6. A steering arrangement as defined in claim 5 when the valve is a pilot operated valve or a solenoid operated valve.

7. A steering arrangement as defined in claim 5 including a first sensor for sensing when the valve is in the first position and/or including a second sensor for sensing when the valve is in the second position.

8. A steering arrangement as defined in claim 3 wherein the pump system includes a first pump for supplying pressurised fluid to the first steering unit and a second pump for supplying pressurised fluid to the second steering unit.

9. A steering arrangement as defined in claim 1 wherein pressurised fluid is supplied to one or more of the first, second, third and fourth hydraulic pressure chambers when the steering system is in the first mode at a pressure lower than the pressure of the fluid supplied to one or more of the first, second, third and fourth hydraulic pressure chambers when the steering system is in the second mode.

10. A steering arrangement as defined in claim 9 wherein a relief valve is arranged to relieve the pressure of the pressurised fluid at a first level when the steering system is operating in the first mode and is arranged to relieve pressure at a second level, higher than the first level when the steering system is operating in the second mode.

11. A steering arrangement as defined in claim 3 wherein the steering system has a third mode wherein only one of the first steering unit and second steering unit selectively supplies fluid to the first and third hydraulic pressure chamber to steer in a first direction; or
said only one of the first steering unit and second steering unit selectively supplies fluid to the second and fourth hydraulic pressure chamber to steer in the second direction;
such that the steering ratio is lower in the third mode than in the first mode.

12. A steering arrangement as defined in claim 1 wherein the steering arrangement has a fourth mode wherein pressurised fluid is supplied by an automatic steering system to one of the first and third hydraulic pressure chambers to steer in the first direction or wherein pressurised fluid is supplied by the automatic steering system to one of the second and fourth hydraulic pressure chambers to steer in the second direction.

13. A steering arrangement including a first hydraulic pressure chamber, a second hydraulic pressure chamber, a third hydraulic pressure chamber and a fourth hydraulic pressure chamber, the first and third pressure chambers being selectively operable to steer in a first direction and the second and fourth pressure chambers being selectively operable to steer in a second direction,
a pump system for supplying pressurized fluid to a steering system,
the steering system being operable to supply the pressurized fluid to one or more of the first, second, third and fourth hydraulic pressure chambers,
the steering system having a primary mode wherein pressurized fluid is simultaneously supplied to the first and third hydraulic pressure chambers to steer in the first direction or wherein pressurized fluid is simultaneously supplied to the second and fourth hydraulic pressure chambers to steer in the second direction, and
the steering system having a secondary mode wherein pressurized fluid is supplied by an automatic steering system to only the first hydraulic pressure chamber to steer in the first direction or wherein pressurized fluid is supplied by an automatic steering system to only the second hydraulic pressure chamber to steer in the second direction.

14. A steering arrangement as defined in claim 13 wherein with the steering system in the secondary mode, the third pressure chamber is connected to the fourth pressure chamber.

15. A steering system as defined in claim 13 including
a first steering unit,
a second steering unit,
wherein with the steering system in the primary mode,
the first steering unit selectively supplies pressurized fluid to one of the first or third chamber simultaneously with the second steering unit supplying pressurized fluid to the other of the first or third chamber to steer in the first direction, or
the first steering unit selectively supplies pressurized fluid to one of the second or fourth chamber simultaneously with the second steering unit supplying pressurized fluid to the other of the second or fourth chamber to steer in the second direction.

16. A steering

Assignees

• Bamford Excavators Ltd

Inventors

• Young Richard Frederick George
• Clarke Nathan James
• Cadman Richard Edward

Classifications

• B62D5/30

  Safety devices, e.g. alternate emergency power supply or transmission means to ensure steering upon failure of the primary steering means · CPC title

• B62D5/093 Primary

  Telemotor driven by steering wheel movement (hydraulic steering gear B62D3/14) · CPC title

• B62D5/008 Primary

  Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear · CPC title

• A01B69/007

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

• A01B69/00 Primary

  Steering of agricultural machines or implements; Guiding agricultural machines or implements on a desired track · CPC title