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A countershaft-type automatic power transmission in which a countershaft gear assembly is operated by a hydraulic control system controlled by electric control means responsive to various operational variables of a vehicle and in which a clutch assembly is operated between the coupled and uncoupled

A countershaft-type automatic power transmission in which a countershaft gear assembly is operated by a hydraulic control system controlled by electric control means responsive to various operational variables of a vehicle and in which a clutch assembly is operated between the coupled and uncoupled conditions by clutch control valve means which is also controlled by the electric control means, the power transmission further featuring throttle valve control means adapted to move the carburetor throttle valve to a position to produce an idling condition in the engine independently of the accelerator pedal when the clutch assembly is in the uncoupled condition.

대표청구항 ▼

In an automatic countershaft power transmission for an automotive vehicle comprising an internal combustion engine including a mixture supply system having a throttle valve to be operated by an accelerator pedal of the vehicle; a countershaft transmission gear assembly including a transmission input

In an automatic countershaft power transmission for an automotive vehicle comprising an internal combustion engine including a mixture supply system having a throttle valve to be operated by an accelerator pedal of the vehicle; a countershaft transmission gear assembly including a transmission input shaft, a transmission mainshaft substantially in line with the input shaft, a transmission counershaft substantially parallel with the mainshaft and a plurality of gears on the transmission input shaft, mainshaft and countershaft and arranged to be capable of producing a neutral gear condition, a plurality of forward-drive gear conditions and at least one reverse-drive gear condition; a clutch assembly disposed between the output shaft of the engine and said transmission input shaft and having a fully coupled condition between the engine output shaft and the transmission input shaft and an uncoupled condition disconnecting the transmission input shaft from the engine output shaft; electrically operated hydraulic control system operatively connected to said transmission gear assembly; gearshift control means operative to actuate said hydraulic control system for selectively producing said neutral, forward-drive and reverse-drive gear conditions depending upon predetermined operational parameters of the vehicle; electrically operated throttle-valve actuating means operative to actuate said throttle valve into an idling position independently of the accelerator pedal of the vehicle; and electric throttle valve control means operative to actuate said throttle-valve actuating means to move the throttle valve into an idling position independently of the accelerator pedal, the improvement comprising fluid-operated clutch actuating means operatively connected to said clutch assembly and having a variable volume control chamber for producing the coupled and uncoupled condition in the clutch assembly when the control chamber is expanded and contracted, respectively, electrically operated clutch control valve means connected to said clutch actuating means, and electric valve control means responsive to preselected operational parameters of the vehicle for controlling the clutch control valve means to continuously vary the volume of said control chamber depending upon said preselected operational parameters, said valve control means, said gearshift control means and said throttle-valve control means being cooperative with each other for actuating said clutch control valve means to contract said control chamber in response to a shift being made between any of said gear conditions, moving said throttle valve into the idling position thereof independently of the accelerator pedal when said clutch control valve means is in a condition establishing the uncoupled condition in said clutch assembly, and producing an upshift between said forward-drive gear conditions when said throttle-valve control means is in a condition having said throttle-valve actuating means actuated and said valve control means is in a condition having the clutch control valve means actuated to produce the uncoupled condition in the clutch assembly under conditions in which the vehicle speed is higher than a predetermined level, said clutch control valve means including a vacuum port communicating with a source of vacuum and communicable with said control chamber for causing the control chamber to contract when communication is provided between the control chamber and said vacuum source through said vacuum port, and a plurality of air ports each communicating with the atmosphere and communicable with said control chamber, the individual air ports having different cross sectional areas and being arranged in series with said control chamber, said valve control means being operative to have said air ports selectively and successively brought into communication with said control chamber for allowing atmospheric air into the control chamber at stepwise variable rates and thereby causing the control chamber to expand at stepwise variable rates so that said clutch assembly is operated from the uncoupled condition to the fully coupled condition at stepwise variable rates.