Control units for vehicle powersteering mechanisms

Abstract

The present invention relates to a control unit for a vehicle powersteering mechanism comprising a housing having an inlet for connection to a source of fluid under pressure, an outlet for returning hydraulic fluid under pressure to said source, a pair of ports for connection to a hydraulic servomotor the movement of which controls the steering of the dirigible wheels of the vehicle, a hydraulic motor provided with a rotatable element and a follower element in operative combination with a distributor valve means provided with at least one displaceable body, said combination being operable on rotation of a control shaft connected thereto to divert hydraulic fluid flowing from said inlet through said housing to said outlet to one of said ports, and thus to its associated chamber of said servomotor, via said hydraulic motor, the hydraulic fluid being exhausted from the other chamber of the servomotor to said outlet, via said other port.

I claim:  .[.1. A control unit for vehicle powersteering mechanism comprising: 
       a housing having an inlet for connection to a source of hydraulic fluid under pressure and an outlet for returning hydraulic fluid to said source; 
       a pair of ports for connection to a double chamber hydraulic servomotor the movement of which controls the steering of dirigible wheels of the vehicle; 
       a hydraulic motor provided with a rotatable element and a follower element; 
       a distributor valve means provided with at least one displaceable body, in the form of a sleeve, angularly displaceable with respect to a neutral position, said distributor valve means being operable on rotation of a control shaft connected thereto to divert hydraulic fluid flowing from said inlet through said housing to said outlet to one of said ports and thus to its associated chamber of said servomotor, via said hydraulic motor, the hydraulic fluid being exhausted from the other chamber of the servomotor to said outlet via said other port; 
       means adapted to form a direct connection of said rotatable element of the motor to said control shaft; 
       means adapted to form a mechanical connection of said follower element of the motor to the sleeve like displaceable body of said rotatable distributor valve means; 
       means adapted to limit the displacement of said sleeve like displaceable body with respect to the stationary part of said distributor valve means, and with respect to said neutral position; 
       a plurality of circumferentially spaced longitudinally extending passages provided in said sleeve like displaceable distributor body to feed hydraulic fluid from said inlet, via said motor, to one or the other of said ports when said sleeve like displaceable distributor body is in its displaced position with respect to the neutral position; 
       first passages in said housing communicating with said inlet and with said longitudinally extending passages; 
       second passages in said housing emanating from each of said ports and communicating with said longitudinally extending passages; and 
       radially extending passages in said sleeve like displaceable distributor body communicating with said first passages in said housing, for feeding hydraulic fluid arriving from said inlet to said distributor valve means..]. .Iadd. 2. A control unit for a vehicle powersteering mechanism comprising: 
       a housing having an inlet for connection to a source of hydraulic fluid under pressure and an outlet for returning hydraulic fluid to said source; 
       a double chamber hydraulic servomotor; 
       a pair of ports in said housing selectively operatively connected to said double chamber hydraulic servomotor and selectively operatively connected to said inlet and outlet; 
       a hydraulic motor provided with a rotatable element and a follower element being operatively disposed within said housing; 
       a distributor valve means including a stationary member and one sleeve like displaceable body having an outer wall of a predetermined thickness with an outer surface, a plurality of circumferentially spaced longitudinally extending bores provided within the thickness of the outer wall of said sleeve like displaceable body, a plurality of radially extending passages in said sleeve like displaceable distributor body projecting through a portion of said outer wall to the outer surface thereof, each of said longitudinally extending bores being in communication in said outer wall with at least two longitudinally spaced apart radially extending passages, said rotatable element engaging a portion of said outer surface of said sleeve like displaceable body and enclosing one of said spaced apart radially extending passages; 
       said distributor valve means being solely angularly displaceable with respect to a neutral position, and being operable on rotation of a control shaft connected thereto to simultaneously divert hydraulic fluid flowing from said inlet through a first series of selective radial passages and longitudinally extending bores to said hydraulic motor and through a second series of selective radial passages and longitudinally extending bores to one of said ports and thus to its associated chamber of said servomotor, hydraulic fluid being exhausted from the other chamber of the servomotor through said other port, said distributor valve means and said outlet; 
       a mechanical connection formed between said follower element of said hydraulic motor and said sleeve like displaceable body; and 
       means adapted to limit the displacement of said sleeve like displaceable body with respect to the stationary member of said distributor valve means and with respect to said neutral position. .Iaddend..Iadd. 3. A control unit for a vehicle powersteering mechanism according to claim 2, wherein said sleeve like displaceable distributor body is an elongated cylinder having an open central portion and being positioned within a cylindrical opening in said housing, said sleeve like displaceable distributor body being rotated to a limited extent by the interaction of said rotatable element against said follower element. .Iaddend..Iadd. 4. A control unit for a vehicle powersteering mechanism according to claim 2, wherein said means adapted to form a mechanical connection between said follower element and said sleeve like displaceable body includes an elongated shaft keyed to said follower element at one end thereof and being keyed to said sleeve like displaceable body to impart limited rotational motion to said sleeve like displaceable body by the rotational motion imparted to said follower element operatively connected to said rotatable element of said hydraulic motor. .Iaddend..Iadd. 5. A control unit for a vehicle powersteering mechanism according to claim 2, wherein said rotatable element includes a distributor ring with at least one passageway therethrough for communicating hydraulic fluid from said longitudinally extending bores and a corresponding radially extending passage to said hydraulic motor. .Iaddend..Iadd. 6. A control unit for a vehicle powersteering mechanism according to claim 2, wherein said housing includes a cylindrical central opening adapted to receive a cylindrical sleeve which is fixed relative to said housing, said sleeve like displaceable body being operatively positioned within said fixed cylindrical sleeve and being mounted for movement to a limited extent, said rotatable element being an internally toothed motor element disposed within said cylindrical central opening and being operatively positioned adjacent said sleeve like displaceable body, said internally toothed motor element being affixed to said control shaft to rotate therewith, said follower element being an externally toothed motor element positioned in meshing engagement with said internally toothed motor element, said externally toothed motor element being connected via a universally-jointed elongated drive shaft to said sleeve like displaceable body to impart limited rotation thereto. .Iaddend..Iadd. 7. A control unit for a vehicle powersteering mechanism according to claim 6, wherein said rotatable element includes a distributor ring with at least one passageway therethrough for communicating hydraulic fluid from said longitudinally extending bores and a corresponding radially extending passage to said hydraulic motor. .Iaddend..Iadd. 8. A control unit for a vehicle powersteering mechanism according to claim 7, wherein said fixed sleeve includes at least two axially spaced annular chambers in selected communication with said longitudinally extending bores and being individually in direct communication with respective ports for connection to said double chamber hydraulic servomotor. .Iaddend.