Electro-hydraulic gear shifting control for vehicle gears

Claim 1

Electro-hydraulic gear shifting control unit for vehicle gears having hydraulic gear shift controllers for the vehicle transmission gears providing different gear ratios for the vehicle and having a spool valve (9) comprising a unitary housing (12); a single valve spool bore (18) formed in the housing; a main slider spool (22) located in the bore (18); a source of hydraulic pressure (16A; P); ring ducts formed in the slider spool (22); pressure fluid lines (14, 15, 19) connected to said source and providing pressurized hydraulic fluid connected to the bore (18) and drain lines (17) to drain hydraulic fluid from the bore (18); control pressure lines (7, 8) including a shift signal line (7) and a kick-down control line (8) connected to the bore (18) and providing hydraulic pressure fluid to the vehicle transmission; a pressure limiting slider (16) located in said bore in axial alignment with the main slider spool (22) connected to one of the pressure fluid lines (14) and controlling the pressure fluid supplied to the bore (18); said spool valve (9) providing hydraulic pressure, as controlled by said pressure limiting slider (16) over the shift signal line (7) to effect shifting of the gears by supplying a shift control pressure to the gear shift controller upon axial shift of the slider spool (22) in a first direction; a resiliently supported (32) abutment (41) located in said bore (18), in axial alignment with, and facing the slider spool (22) and located to be resiliently engageable by said spool (22) upon movement of said spool in said one direction; the main slider spool (22) being formed with an axial blind bore (21); a first diametrical cross bore (24) communicating the axial blind bore (21) with the outside surface of the slider spool, and terminating in a first ring duct (25) formed in the housing and the spool, and a second diametrical cross bore (27), axially offset from said first cross bore (24) communicating the axial blind bore (21) with the outside surface of the slider spool (22) and terminating in a second ring duct (28) formed in the circumference of the slider spool, one of said ducts (25) being located to communicate with the shift signal line (7) and to have pressure fluid applied thereto upon displacement of the main slider spool (22), and the other of said ducts (28) being located to communicate with the kick-down line (8) and to have pressure fluid applied thereto upon displacement of the main slider spool (22); electro-hydraulic valve means (19, 39, 40, 43, 17; 11) electrically controlled by an engine operating parameter comprising at least one of: (a) engine speed; (b) engine throttle position; and controlling admission of pressurized hydraulic fluid from said source (16A; P) to said bore (18) to act on said slider spool (22) and thereby effect axial shift of said spool in said direction by applying a pressure, as controlled by said electro-hydraulic valve means on the main slider spool (22), the electro-hydraulic valve means providing a bias pressure on the main slider spool (22) and including a hydraulic pressure connection (19) from said pressure source (16A; P) to an axially facing surface (44) of the slider spool; and an electrically controlled valve (43, 40, 39; 11) controlled by said engine operating parameter controlling the pressure of fluid admitted from said pressure source (16A; P) acting on the main slider spool (22), the pressure acting against the axially directed face of the main slider spool (22) being effective to shift the position of the main slider spool (22) in said one direction to effect communication between a hydraulic pressure fluid line (15) connected to said one pressure fluid line (14) and having said controlled pressure therein, and the kick-down pressure line (8) to provide for independent connection of controlled hydraulic pressure to said kick-down pressure line (8) under command of the pressure applied against the axially facing surface of the slider spool (22) as controlled by said electrically controlled valve.