Hydraulically assisted power steering system

Patent metadata

Field	Value
Publication number	US-9545948-B2
Application number	US-201514699450-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Apr 29, 2015
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A power steering assist system includes a hydraulic assist power steering assembly configured to couple to a vehicle steering gear, and a hydraulic pump having an electric motor, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly.

First claim

Having thus described the invention, it is claimed:

1. A power steering assist system comprising:
a hydraulic assist power steering assembly configured to couple to a vehicle steering gear, comprising:
a housing,
a rotary valve assembly,
a differential pressure transducer, and
a rotatable magnetic actuator assembly, the magnetic actuator assembly configured to provide an assist torque to a coupler configured for coupling to the vehicle steering gear; and
an electrically powered hydraulic pump, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly.

2. The system of claim 1 , wherein the rotary valve assembly is a hydraulic rotary valve assembly.

3. The system of claim 1 , further comprising an input shaft disposed at least partially within the housing, the input shaft having a bore, a first end configured to couple to a vehicle steering wheel, and a second end configured to couple to the steering gear, wherein a torsion bar is disposed within the input shaft bore.

4. The system of claim 1 , further comprising an electrical power source electrically coupled to the hydraulic pump, the electrical power source configured to power the electrically powered hydraulic pump.

5. The system of claim 4 , wherein the electrical power source is a vehicle battery.

6. The system of claim 1 , further comprising a controller in signal communication with the hydraulic assist power steering assembly and the electric hydraulic pump, the controller programmed to selectively operate the hydraulic pump between a low speed and a high speed.

7. The system of claim 6 , further comprising a steering wheel angle and velocity sensor in signal communication with the controller, the steering wheel angle sensor configured to determine an angle and velocity of a vehicle steering wheel, wherein the controller is programmed to selectively operate the hydraulic pump between the low speed and the high speed based on the determined angle and velocity of the steering wheel.

8. The system of claim 6 , further comprising a vehicle speed sensor in signal communication with the controller, the vehicle speed sensor configured to determine a speed of a vehicle, wherein the controller is programmed to selectively operate the hydraulic pump between the low speed and the high speed based on the determined vehicle speed.

9. A vehicle comprising:
a steering gear operably coupled to at least one road wheel; and
a hydraulic assist power steering system comprising:
a hydraulic assist power steering assembly coupled to the steering gear comprising:
a housing,
a rotary valve assembly,
a differential pressure transducer, and
a rotatable magnetic actuator assembly, the magnetic actuator assembly configured to provide an assist torque to a coupler coupled to the vehicle steering gear; and

an electrically powered hydraulic pump, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly.

10. The vehicle of claim 9 , wherein the rotary valve assembly is a hydraulic rotary valve assembly.

11. The vehicle of claim 9 , wherein the hydraulic assist power steering assembly further comprises an input shaft disposed at least partially within the housing, the input shaft having a bore, a first end configured to couple to a vehicle steering wheel, and a second end configured to couple to the steering gear, wherein a torsion bar is disposed within the input shaft bore.

12. The vehicle of claim 9 , further comprising an electrical power source electrically coupled to the hydraulic pump, the electrical power source configured to power the electrically powered hydraulic pump.

13. The vehicle of claim 9 , further comprising a controller in signal communication with the hydraulic assist power steering assembly and the electric hydraulic pump, the controller programmed to selectively operate the hydraulic pump between a low speed and a high speed.

14. The vehicle of claim 13 , further comprising a steering wheel angle and velocity sensor in signal communication with the controller, the steering wheel angle sensor configured to determine an angle and velocity of a vehicle steering wheel, wherein the controller is programmed to selectively operate the hydraulic pump between the low speed and the high speed based on the determined angle and velocity of the steering wheel.

15. The vehicle of claim 13 , further comprising a vehicle speed sensor in signal communication with the controller, the vehicle speed sensor configured to determine a speed of a vehicle, wherein the controller is programmed to selectively operate the hydraulic pump between the low speed and the high speed based on the determined vehicle speed.

16. A method of operating a hydraulic assist power steering system comprising: a hydraulic assist power steering assembly configured to couple to a vehicle steering gear, comprising: a housing, a rotary valve assembly, a differential pressure transducer, and a rotatable magnetic actuator assembly, the magnetic actuator assembly configured to provide an assist torque to a coupler configured for coupling to the vehicle steering gear; and an electrically powered hydraulic pump, the hydraulic pump configured to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly, the method comprising:
monitoring a vehicle to determine if a condition exists where a hydraulic assist maneuver may be performed;
operating the electrically powered hydraulic pump at a low speed if the condition does not exist where the hydraulic assist maneuver may be performed, to supply pressurized hydraulic fluid to the hydraulic assist power steering assembly at a low flow rate; and
operating the electrically powered hydraulic pump at a high speed if the condition exists where the hydraulic assist maneuver may be performed, to supply the pressurized hydraulic fluid to the hydraulic assist power steering assembly at a high flow rate.

Assignees

• Steering Solutions Ip Holding

Inventors

• Dutsky Jason A
• Birsching Joel E

Classifications

• B62D5/065 Primary

  characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist · CPC title

• B62D5/064 Primary

  Pump driven independently from vehicle engine, e.g. electric driven pump (B62D5/065 takes precedence) · CPC title

• B62D5/083

  Rotary valves · CPC title

• B62D5/0835

  characterised by means for actively influencing the deflection angle of the valve, e.g. depending on driving parameters · CPC title