Motor vehicles – Surface effect vehicles – Dynamic seal or fluid curtain
Patent
1992-04-23
1994-09-20
Hill, Mitchell J.
Motor vehicles
Surface effect vehicles
Dynamic seal or fluid curtain
180141, 180142, B62D 509
Patent
active
053481100
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a device for actuating the control valve of a hydraulic power steering system for automotive vehicles, the rotary motion of a steering wheel being transmitted by means of a steering shaft, and the steering torque being transmitted by a relative rotation between the steering shaft and a pinion shaft, and wherein the control valve is a linear slide valve.
BACKGROUND OF THE INVENTION
A device of this type is known from European patent application 0 362 592 wherein a portion of the steering shaft is of bell-type design and the shaft is axially slidably supported. The rotation of the two shafts relative to one another is converted into an axial movement and is transmitted to the control valve by means of pins in the pinion shaft and coulisse-type guides in the bell-type portion of the steering shaft. Because the steering shaft displaces axially in this arrangement, a sophisticated and expensive coupling between the steering wheel and the steering shaft is required to prevent axial displacement of the steering shaft.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a structurally simple device for actuating the control valve which is composed of a small number of component parts and overcomes the known shortcomings.
This object is achieved in that there is provided a sleeve embracing the steering shaft and the pinion shaft which converts the relative rotation between the steering shaft and the pinion shaft into an axial displacement. In a preferred embodiment of the present invention, the sleeve comprises one pair of coulisse-type guides extending axially of the sleeve and one pair of coulisse-type guides extending helically of the sleeve. Pins which are rigidly coupled to the steering shaft and the pinion shaft, respectively, are received in the axially extending coulisse-type guides and the helically extending coulisse-type guides.
A particularly compact design results when the control valve is arranged directly beside the sleeve and the axial displacement is transmitted from the sleeve directly onto the control valve slide through an entraining means on the valve slide, which engages a circumferential groove on the sleeve.
In another embodiment of the invention which is preferred if it is not possible for space reasons to arrange the control valve and sleeve adjacent one another, a double lever is provided for transmitting the axial displacement from the sleeve onto the control valve. One end, a forked end, of the lever engages a circumferential groove of the sleeve, while its other end is attached to the valve slide so as to be rotatable, and the lever is supported so that it is axially immovable yet rotatably movable about a mid-point between the two ends. The position of the mid-point of rotation serves also to adjust the transmission ratio or the reduction ratio of the entire axial displacement.
A preferred embodiment of this invention provides that the lever is pivotably mounted in a housing receiving the control valve or in a part rigidly connected with the valve slide.
In order to compensate for all actuation clearances in the activation of valves, lever and sleeve, it is proposed further that a spring acting upon the valve slide applies a bias thereon. This results in a considerable reduction in hysteresis. Furthermore, the clearances and tolerances can be chosen to be augmented in a size whereby the manufacturing costs are curtailed.
According to another embodiment of this invention, the spring is supported on the valve slide by a sleeve-shaped part which is attached to the valve slide and embraces in particular the end area of the valve slide and support for the spring on the side opposite to the valve slide is provided by a closure element which closes the bore accommodating the spring.
In a particularly suitable embodiment of the present invention, the support of the lever is a spherical joint bearing.
According to another preferred embodiment of this invention, the portion of the lever making ca
REFERENCES:
patent: 4003446 (1977-01-01), Fleury
patent: 4607717 (1986-08-01), Nakayama
patent: 4856608 (1989-08-01), Adams
Baier Joachim
Beer Wilhelm
Drott Peter
Kahrs Manfred
Klein Hans-Christof
Hill Mitchell J.
Lewis J. Gordon
Seitter Robert P.
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