Hydraulic fluid control device for a hydraulic power-assisted steering system
View Patent ↗A hydraulic power-assisted steering system ( 10 ) includes a pump ( 12 ) containing hydraulic fluid. A rack and pinion housing ( 19 ) is operatively connected to the pump ( 12 ) via a conduit line ( 16 ). A hydraulic fluid control device ( 80 ) is operatively disposed between the pump ( 12 ) and the rack and pinion housing ( 19 ), the hydraulic fluid control device ( 80 ) having a passageway ( 82 ) formed therethrough to allow hydraulic fluid to flow from the pump ( 12 ) to the rack and pinion housing ( 19 ). An electromagnet ( 94 ) is operatively coupled to the fluid control device ( 80 ). An electronic control unit ( 96 ) is adapted to receive at least one input signal ( 98, 100 ) from at least one input source so as to generate an output signal ( 102 ) to the hydraulic fluid control device ( 80 ) so as to selectively control the flow of hydraulic fluid from the pump ( 12 ) to the rack and pinion housing ( 19 ). According to the present invention, the fluid control device ( 80 ) is formed from a magnetostrictive alloy material which is capable of changing the size of the passageway ( 82 ) in the hydraulic fluid control device ( 80 ) in response to an applied magnetic field, whereby the electronic control unit ( 96 ) is operative to selectively control the physical shape or size of the passageway ( 82 ) of the hydraulic fluid control device ( 80 ), thereby selectively controlling the flow of hydraulic fluid from the pump ( 12 ) to the rack and pinion housing ( 19 ).
1. A hydraulic power-assisted steering system comprising:
a pump containing hydraulic fluid;
a rack and pinion housing operatively connected to said pump via a conduit line;
a hydraulic fluid control device operatively disposed between said pump and said rack and pinion housing, said hydraulic fluid control device having a passageway formed therethrough to allow hydraulic fluid to flow from said pump to said rack and pinion housing;
an electromagnet operatively coupled to said fluid control device; and
an electronic control unit adapted to receive at least one input signal from at least one input source so as to generate an output signal to said hydraulic fluid control device so as to selectively control the flow of hydraulic fluid from said pump to said rack and pinion housing;
wherein said fluid control device is formed from a magnetostrictive alloy material which is capable of changing the size of said passageway in said hydraulic fluid control device in response to an applied magnetic field, whereby said electronic control unit is operative to selectively control the physical shape or size of said passageway of said hydraulic fluid control device thereby selectively controlling the flow of hydraulic fluid from said pump to said rack and pinion housing.
2. The hydraulic fluid control device according to claim 1 , wherein said at least one input signal from at least one input source includes at least one input signal from a vehicle speed sensor and a steering rate sensor.
3. The hydraulic fluid control device according to claim 1 , wherein said electro-magnet is integral with said rack and pinion housing.
4. The hydraulic fluid control device according to claim 1 , wherein said electromagnet is disposed adjacent an inlet port of said rack and pinion housing.
5. The hydraulic fluid control device according to claim 1 , wherein said electromagnet is disposed adjacent said pump.
6. The hydraulic fluid control device according to claim 1 , wherein said electromagnet is disposed in said conduit line.
7. The hydraulic fluid control device according to claim 1 , wherein said electro-magnet defines a portion of said inlet port.
8. The hydraulic fluid control device according to claim 1 , wherein said fluid control device includes a fluid control device housing and a fluid control body disposed within said fluid control device housing.
9. The hydraulic fluid control device according to claim 8 , wherein said body is formed from said magnetostrictive alloy material.
10. The hydraulic fluid control device according to claim 8 , wherein said fluid control device housing is formed from a substantially rigid material.
11. The hydraulic fluid control device according to claim 10 , wherein said substantially rigid material is formed from other than a magnetostrictive alloy material.
12. The hydraulic fluid control device according to claim 1 , wherein said magnetostrictive alloy material is capable of changing a diameter of said passageway in response to said applied magnetic field.
13. The hydraulic fluid control device according to claim 12 , wherein said magnetostrictive alloy material is capable of changing said diameter of said passageway between a first diameter and a second diameter.
14. The hydraulic fluid control device according to claim 13 , wherein said first diameter is larger than said second diameter.
15. A hydraulic fluid control device adapted for use in a hydraulic power-assisted steering system, said hydraulic fluid control device comprising:
a hydraulic fluid control device operatively disposed between a pump and a rack and pinion housing of the hydraulic power-assisted steering system, said hydraulic fluid control device having a passageway formed therethrough to allow hydraulic fluid to flow from the pump to the rack and pinion housing;
an electromagnet operatively coupled to said fluid control device; and
an electronic control unit adapted to receive input at least one input signal from at least one input source so as to generate an output signal to said hydraulic fluid control device so as to selectively control the flow of hydraulic fluid the pump to the rack and pinion housing;
wherein said fluid control device is formed from a magnetostrictive alloy material which is capable of changing the size of said passageway in said hydraulic fluid control device in response to an applied magnetic field, whereby said electronic control unit is operative to selectively control the physical shape or size of said passageway of said hydraulic fluid control device thereby selectively control the flow of hydraulic fluid from the pump to the rack and pinion housing.
16. The hydraulic fluid control device according to claim 15 , wherein said at least one input signal from at least one input source includes at least one input signal from a vehicle speed sensor and a steering rate sensor.
17. The hydraulic fluid control device according to claim 15 , wherein said electromagnet is integral with said rack and pinion housing.
18. The hydraulic fluid control device according to claim 15 , wherein said electromagnet is disposed adjacent an inlet port of said rack and pinion housing.
19. The hydraulic fluid control device according to claim 18 , wherein said electromagnet defines a portion of said inlet port.
20. The hydraulic fluid control device according to claim 15 , wherein said electromagnet is disposed adjacent said pump.
21. The hydraulic fluid control device according to claim 15 , wherein said electromagnet is disposed in a conduit line operatively connecting said rack and pinion housing and said pump.
22. The hydraulic fluid control device according to claim 15 , wherein said fluid control device includes a fluid control device housing and a fluid control body disposed within said fluid control device housing.
23. The hydraulic fluid control device according to claim 22 , wherein said body is formed from said magnetostrictive alloy material.
24. The hydraulic fluid control device according to claim 22 , wherein said fluid control device housing is formed from a substantially rigid material.
25. The hydraulic fluid control device according to claim 24 , wherein said substantially rigid material is formed from other than a magnetostrictive alloy material.
26. The hydraulic fluid control device according to claim 15 , wherein said magnetostrictive alloy material is capable of changing a diameter of said passageway in response to said applied magnetic field.
27. The hydraulic fluid control device according to claim 26 , wherein said magnetostrictive alloy material is capable of changing said diameter of said passageway between a first diameter and a second diameter.
28. The hydraulic fluid control device according to claim 27 , wherein said first diameter is larger than said second diameter.