EP0071909A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Vehicular power steering system
Assignee: Nissan Motor Co Ltd
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Filing: 1982-07-30
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Granted: —
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Expires: 2002-07-30
Abstract
Abstract in a vehicular power steering system, the hydraulic fluid supply to a hydraulic power actuator (3) is controlled in accordance with the vehicle speed and the angular velocity of the steering wheel (4). Preferably, the fluid supply is reduced so that the steering effort becomes heavier as the vehicle speed increases while the fluid supply is increased when the angular velocity of the steering wheel (4) is high. To control the fluid supply, there is provided a bypass valve means (8) for draining a portion of the fluid flow to bypass the power actuator (3), and control means (10) for producing a control signal to control the bypass valve means (8) in accordance with the vehicle speed and the angular velocity of the steering wheel (4).
Inventors
- 👤 Masafumi Nakayama
- 👤 Tokiyoshi Yanai
- 👤 Masato Fukino
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 12:10
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/065; B62D6/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
228 words
A vehicular power steering system comprising a steering mechanism, a hydraulic power cylinder for transmitting mechanical work converted from hydraulic power to said steering mechanism for effecting power assistance, a fluid pump, a servo valve connected with said pump through a supply line and a return line, for controlling the fluid flow and introducing a fluid pressure to said power cylinder in accordance with the movement of the steering wheel of said steering mechanism, and bypass control means disposed in a bypass line connected between the supply line and the return line to bypass said servo valve, for controlling the amount of the fluid supply to said servo valve through said supply line, thereby to control the degree of power assistance by controlling the flow rate through said bypass line, characterized by a vehicle speed sensor (11) for sensing the speed of the vehicle, an angle sensor (17) for sensing an angular displacement of the steering wheel, and control means (10) for producing a control signal to be applied to said bypass valve means (8) and thereby to control the fluid supply to said servo valve (3), said control means (10) being connected with said speed sensor (11) and said angle sensor (17) and controlling the fluid supply to said servo valve (3) in accordance with the vehicle speed and the angular velocity of the steering wheel (4).
Claim 2
Dependent Claim
228 words
A vehicular power steering system comprising a steering mechanism, a hydraulic power cylinder for transmitting mechanical work converted from hydraulic power to said steering mechanism for effecting power assistance, a fluid pump, a servo valve connected with said pump through a supply line and a return line, for controlling the fluid flow and introducing a fluid pressure to said power cylinder in accordance with the movement of the steering wheel of said steering mechanism, and bypass control means disposed in a bypass line connected between the supply line and the return line to bypass said servo valve, for controlling the amount of the fluid supply to said servo valve through said supply line, thereby to control the degree of power assistance by controlling the flow rate through said bypass line, characterized by a vehicle speed sensor (11) for sensing the speed of the vehicle, an angle sensor (17) for sensing an angular displacement of the steering wheel, and control means (10) for producing a control signal to be applied to said bypass valve means (8) and thereby to control the fluid supply to said servo valve (3), said control means (10) being connected with said speed sensor (11) and said angle sensor (17) and controlling the fluid supply to said servo valve (3) in accordance with the vehicle speed and the angular velocity of the steering wheel (4).
Claim 3
Dependent Claim
65 words
A power steering system according to claim 1, characterized in that said control means (10) reduces the fluid supply to said servo valve (3) as the vehicle speed increases, and further controls the fluid supply in such a manner that the rate of the fluid supply to said servo valve (3) is a monotone nondecreasing function of the angular velocity of the steering wheel (4).
Claim 4
Dependent Claim
204 words
A power steering system according to claim 2, characterized in that said control means (10) comprises a differentiator (19) whose input terminal is connected with said angle sensor (17) and whose output signal is proportional to the time rate of change of the input signal, a first operation circuit (20) which is connected with said differentiator (19) to receive its output signal and produces an output signal indicative of the amount of the fluid supply to said servo valve in accordance with the angular velocity of the steering wheel (4), a second operation circuit (22) which is connected with said vehicle speed sensor (11) to receive its output signal and produces an output signal indicative of the amount of the fluid supply to said servo valve (3) in accordance with the vehicle speed, a comparator circuit (21) connected with said first operation circuit (20) and said second operation circuit (22) for producing an output signal which is equal to the greater one of both the output signals of said first operation circuit (20) and said second operation circuit (22), and an amplifier (23) connected with said comparator circuit (21) for producing said control signal by amplifying the output signal of said comparator circuit (21).
Claim 5
Dependent Claim
195 words
A power steering system according to claim 2, characterized in that said control means (10) comprises a differentiator (9) whose input terminal is connected with said angle sensor (17) and whose output signal is proportional to the time rate of change of the input signal, a first operation circuit (24) which is connected with said differentiator (19) to receive its output signal and produces an output signal indicative of the amount of the fluid supply demanded by said power cylinder (6) in accordance with the angular velocity of the steering wheel (4), a second operation circuit (22) which is connected with said vehicle speed sensor (11) to receive its output signal and produces an output signal indicative of the amount of the fluid supply to said servo valve (3) in accordance with the vehicle speed, an adder circuit (25) connected with said first and second operation circuits (24,22) for producing an output signal indicative of the sum of the output signals of the first and second operation circuits (24, 22), and an amplifier (23) connected with said adder circuit (25) for producing said control signal by amplifying the output signal of said adder circuit (25).
References Cited (Backward Citations)
No citation records indexed.
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