Motor vehicles – Including one or more ski-like or runner members – With at least one surface-engaging propulsion element
Patent
1986-06-13
1988-11-15
Love, John J.
Motor vehicles
Including one or more ski-like or runner members
With at least one surface-engaging propulsion element
91434, 180143, B62D 506
Patent
active
047842350
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a power steering apparatus for an automobile, and more particularly, to a control valve of a steering oil pressure which is supplied to a reaction chamber of a main control valve of a power steering apparatus.
DESCRIPTION OF THE PRIOR ART
In a power steering apparatus, a control oil pressure is supplied to a power cylinder from a pump through a main control valve while a steering oil pressure is derived by a branch from the pump output. There is provided an auxiliary control valve which controls the steering oil pressure in accordance with a control signal which is formed on the basis of an output from a vehicle speed sensor, and the steering oil pressure which is regulated by the auxiliary control valve is introduced into the reaction chamber within the main control valve, thereby producing a steering force which depends on the vehicle speed.
A typical example of a control valve which controls a steering oil pressure supplied to a reaction chamber is disclosed in U.S. Pat. No. 3,744,515 issued July 10, 1973. In this control valve, a steering oil pressure developed by the pump is passed initially through a variable throttle and then through a fixed throttle, with the variable throttle being adjusted in accordance with a vehicle speed. The variable throttle comprises a main cylindrical spool slidably disposed in a valve casing with its opposite ends being supported by springs, and a sub-spool which is slidably fitted into the main spool with its opposite ends similarly supported by springs so that a relative displacement between the main spool and the sub-spool changes the area of an opening. The main spool is actuated by the output oil pressure from the pump and the pressure in the reaction chamber of the main control valve while a control signal which varies with the vehicle speed is applied to the sub-spool. A control valve of the type described has a disadvantage that the rigidity of a steering wheel cannot be improved during the time an automotible is running straightforward at a high speed, since the reaction pressure cannot be increased in a region adjacent to the neutral where the variable throttle has the greatest opening area. Another disadvantage relates to a slight increase in the reaction pressure in response to an increase in the steering oil pressure during the time the vehicle stands still, thereby precluding an easy operation of a steering wheel. In respect of the construction, each of the main spool and the sub-spool must be supported by balancing a pair of springs, but it is difficult to maintain a constant balance between the pair of springs.
SUMMARY OF THE INVENTION
The invention has for its object the provision of a compact and inexpensive oil pressure reaction control device for a power steering apparatus which assures a safety running by increasing the rigidity of a steering wheel when the vehicle is running straightforward at a high speed, by supplying an oil pressure of a stable response into a reaction chamber in response to a vehicle speed and other control signals and steering oil pressure while allowing an easy operation of a steering wheel when the vehicle stands still.
The invention is characterized by slidably disposing a sleeve-like main spool, as urged by a spring from one side, within a valve casing which is formed with a flow inlet connected to an oil pump, a return flow outlet, a flow outlet connected to a reaction chamber and a flow outlet connected to a main valve, and by fitting a sub-spool within the main spool so as to slide axially in accordance with a vehicle speed, thereby defining a variable throttle which changes its opening area in accordance with a relative displacement between the main spool and the sub-spool. The arrangement is such that when the vehicle is at rest or at a very slow speed, the variable throttle is opened only to communicate with the main valve and is closed relative to the reaction chamber, while at a higher speed, the sub-spool is moved in a direction to close the variable throttle re
REFERENCES:
patent: 3672137 (1972-09-01), Inoue
patent: 3744515 (1973-07-01), Inoue
patent: 4434866 (1984-03-01), Duffy
patent: 4531602 (1985-07-01), Roehringer
patent: 4637484 (1987-01-01), Ijiri et al.
Hirakushi Shuzo
Ijiri Waichiro
Adams Bruce L.
Koyo Seiko Kabushiki Kaisha
Love John J.
Watts Charles R.
Wilks Van C.
LandOfFree
Oil pressure reaction control valve for power steering apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oil pressure reaction control valve for power steering apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oil pressure reaction control valve for power steering apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1098545