Steering force control device for power steering apparatus
First Claim
1. A steering force control device for a power steering apparatus, having a hydraulic pressure reaction chamber provided inside a main valve for controlling a relative torsional angle between an input shaft connected to a steering wheel and an output shaft connected to the power steering apparatus in response to a fluid pressure applied to the hydraulic pressure reaction chamber so as to apply a hydraulic reaction to the steering wheel, the steering force control device comprising:
- a main pump driven by an engine of a vehicle to feed a first pressurized fluid to said power steering apparatus through said main valve;
a sub-pump driven by the engine of the vehicle to supply a second pressurized fluid separately from the first pressurized fluid to the hydraulic pressure reaction chamber within said main valve;
a first oil passage connected between a discharge opening of said main pump and said main valve to transfer said first pressurized fluid from the main pump to the main valve;
second and third oil passages for reciprocatingly transporting said first pressurized fluid between said main valve and said power steering apparatus to power-assist in driving the power steering apparatus;
a fourth oil passage for circulating said first fluid, which has been transported from said power steering apparatus to said main valve, to a tank which receives said first fluid from said main valve;
a fifth oil passage for supplying said second pressurized fluid from a discharge opening of said sub-pump to the hydraulic pressure reaction chamber within said main valve;
first and second branch passages which are branched from said fifth oil passage to circulate said second fluid to said tank;
first throttle means installed in said first branch passage and actuated by a hydraulic circuit pressure of the first pressurized fluid fed from said main pump to said main valve for controlling the pressure of said second fluid applied to the hydraulic pressure reaction chamber;
a third branch passage connected between said first throttle means and the discharge opening of the main pump to transmit said hydraulic circuit pressure of the first pressurized fluid to said first throttle means; and
second throttle means installed in said second branch passage and actuated in response to the speed of the vehicle and the steering angle thereof to control the pressure of said second fluid applied to the hydraulic pressure reaction chamber.
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Accused Products
Abstract
An apparatus for controlling a steering force of a vehicle which uses a power steering apparatus in which a driving shaft for a sub-pump for feeding pressure oil into a hydraulic pressure reaction chamber provided internally of a main valve and a main pump for supplying pressure oil for the power steering apparatus is made common to both said pumps to increase an discharge amount and hydraulic pressure of the sub-pump. When speed information and steering angle information of the vehicle are obtained, the hydraulic pressure fed to the hydraulic pressure reaction chamber is controlled by a throttle means subjected to numerical control by output signal of the controller which is provided with predetermined data according to the travelling state of the vehicle and the other throttle means by way of analog control wherein a variation of road resistance is sensitively transmitted as a variation of hydraulic pressure to vary an opening in response thereto, thus always obtaining a proper steering force. The controller further processes an engine revolution information in addition to the foregoing informations to thereby provide a failsafe function for the steering force control device according to the present invention.
21 Citations
30 Claims
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1. A steering force control device for a power steering apparatus, having a hydraulic pressure reaction chamber provided inside a main valve for controlling a relative torsional angle between an input shaft connected to a steering wheel and an output shaft connected to the power steering apparatus in response to a fluid pressure applied to the hydraulic pressure reaction chamber so as to apply a hydraulic reaction to the steering wheel, the steering force control device comprising:
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a main pump driven by an engine of a vehicle to feed a first pressurized fluid to said power steering apparatus through said main valve; a sub-pump driven by the engine of the vehicle to supply a second pressurized fluid separately from the first pressurized fluid to the hydraulic pressure reaction chamber within said main valve; a first oil passage connected between a discharge opening of said main pump and said main valve to transfer said first pressurized fluid from the main pump to the main valve; second and third oil passages for reciprocatingly transporting said first pressurized fluid between said main valve and said power steering apparatus to power-assist in driving the power steering apparatus; a fourth oil passage for circulating said first fluid, which has been transported from said power steering apparatus to said main valve, to a tank which receives said first fluid from said main valve; a fifth oil passage for supplying said second pressurized fluid from a discharge opening of said sub-pump to the hydraulic pressure reaction chamber within said main valve; first and second branch passages which are branched from said fifth oil passage to circulate said second fluid to said tank; first throttle means installed in said first branch passage and actuated by a hydraulic circuit pressure of the first pressurized fluid fed from said main pump to said main valve for controlling the pressure of said second fluid applied to the hydraulic pressure reaction chamber; a third branch passage connected between said first throttle means and the discharge opening of the main pump to transmit said hydraulic circuit pressure of the first pressurized fluid to said first throttle means; and second throttle means installed in said second branch passage and actuated in response to the speed of the vehicle and the steering angle thereof to control the pressure of said second fluid applied to the hydraulic pressure reaction chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a power steering system having a power steering apparatus driven to effect power-assisted steering of a vehicle in response to application of a pressurized fluid to the power steering apparatus:
- a main pump driven by an engine of the vehicle for producing a first pressurized fluid;
a sub-pump driven by the engine for producing a second pressurized fluid independently of the first pressurized fluid;
a housing;
an output shaft rotatably supported in the housing and connected to the power steering apparatus to drive the same;
an input shaft torsionally coupled to the output shaft in the housing and manually rotatively driven relative to the output shaft to transmit a torsional torque to the output shaft;
valve means disposed in the housing for distributing the first pressurized fluid fed from the main pump to the power steering apparatus in accordance with the relative rotation between the input and output shafts so as to assist in driving the power steering apparatus;
reaction means disposed in the housing for slideably coupling the input and output shafts with each other in response to the pressure of the second pressurized fluid fed from the sub-pump to the reaction means so as to transmit a reaction torque from the output shaft to the input shaft during the manual operation of the input shaft; and
control means connected between the sub-pump and the reaction means for regulating the pressure of the second pressurized fluid in accordance with a vehicle operating condition. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
- a main pump driven by an engine of the vehicle for producing a first pressurized fluid;
Specification