A governor assembly for the control system of an automatic transmission is composed of two governors, a primary governor and a secondary governor, each mounted on the output shaft of the transmission in a symmetrical arrangement with respect to the axis of the output shaft. Modulator pressure produced by the primary governor is applied to the secondary governor, by which governor pressure as a pressure signal for actuating shift valves for controlling the transmission is established. The modulat...

A hydraulic pressure control device is provided for an automatic transmission including a hydraulic torque-converter or fluid coupling, a change speed gearing, a hydraulic servo for brake bands, clutches and the like. A relay valve is added to a pressure regulator valve for controlling the hydraulic pressure applied to the servo, and in response to the actuation of an automatic shift valve an oil line to the servo is communicated with a pressure control chamber in the pressure regulator valve so...

A throttling control valve having a spool-like valve element which is gradually shifted in accordance with increase of a control fluid pressure so as to provide four different passage connections therethrough so as to be able to provide four different flow resistances, and a system for controlling downshift timing of an automatic transmission for vehicles which employs this throttling control valve so as to change delay time in supplying fluid pressure to a lower speed friction engaging means in...

A hydraulic control system for an automatic transmission including a transmission gear system provided with hydraulic servos for the brake bands or the clutches, wherein, in addition to a pressure regulator valve for controlling pressure oil applied to said servos and shift valves for establishing low and high forward drive ratios, a diaphragm mechanism is provided to additionally apply the engine intake manifold vacuum to the pressure regulator valve so that said drive ratios are varied by the ...

A four-forward-speed transmission comprising an intermediate shaft, two sets of single pinion planetary gears, and a double pinion planetary gear, with all of said components being concentrically arranged between an input shaft and an output shaft. A first clutch is adapted to apply an input to the intermediate shaft, and a second clutch is adapted to apply an input to both sun gears of the two sets of single pinion planetary gears which are integrally connected. A first brake is adapted to rest...

A shift signal control system having an engine torque responsive signal generator, a vehicle speed responsive signal generator, and a plurality of discriminating circuits generating an output signal when one of these two signals or the relation between these two signals satisfies a predetermined condition. At least one of the discriminating circuits is disconnectably connected with an OR circuit through a switch while the remaining discriminating circuits are directly connected with the OR circu...

A four wheel drive power transmission for a vehicle has a center differential device for distributing rotational power supplied from an engine to a front wheel propeller shaft and a rear wheel propeller shaft at a variable torque dividing ratio therebetween, and a mechanism for controlling the center differential device so as to vary the torque dividing ratio according to the magnitude of the torque of the rotational power supplied from the engine so that the torque dividing ratio is varied towa...

A breathing system for an automatic transmission including a fluid torque converter, an oil pump, an overdrive means and an auxiliary gear means each having its own housing and being air-tightly connected with each other in series in said order, the system including a passage extending through the housings of the oil pump, the overdrive means and the auxiliary gear means for releasing the internal space confined in the assembly of the housings to the atmosphere, the passage including a loop port...

Improved shift control of the present invention is used in an engine driven vehicle having an automatic transmission. Load indicating apparatus responds to the operational load characteristics of the vehicle and produces outputs indicative of variations therein, while a responsively coupled first shift point computing apparatus effects the gear change signal for the transmission when the output indicates a certain load characteristic. A second shift point computer is responsively coupled to the ...

A control system for an automatic transmission for an automotive vehicle comprising a combination of a hydraulic control section and an electrical control section. The hydraulic control section includes a servo capacity control value connected to a plurality of hydraulic servos for controlling fluid pressure supplied to the hydraulic servos during a shift from one speed ratio to another by discharging a portion of fluid under pressure from at least one of the hydraulic servos or from an associat...