Oil pressure control means for an automatic transmission
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorShigeru Moriya
Life of this patent
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Abstract
An oil pressure control means for operating an automatic transmission for automobiles in a manner to establish various speed shift stages in accordance with the balance of the throttle pressure and the governor pressure, including a combination of a thermo-sensitive control means operable in response to the engine temperature and an oil passage change-over means, said combination being adapted to supply the line pressure in lieu of the throttle pressure to a speed shift valve which establishes the highest speed stage when the engine is not yet warmed up thereby positively shifting the speed shift valve to the lower speed shift position by over-balancing the governor pressure by the line pressure.
Claims7
An oil pressure control means for an automatic transmission having a fluid torque converter and a speed shift gear means including a speed shift gear mechanism and a plurality of friction engaging means, said oil pressure control means comprising a source of oil pressure, a line pressure regulating valve which generates a line pressure from the oil pressure of said source, a throttle pressure regulating valve which generates a throttle pressure corresponding to the throttle opening, a governor valve which generates a governor pressure corresponding to the vehicle speed, a manual shift valve for shifting speed ranges, and a plurality of speed shift valves which change over the supply of oil pressure to said friction engaging means of said speed shift gear means depending upon the balance of said throttle pressure and said governor pressure, a thermo-sensitive means including a thermo-sensitive element for sensing the engine temperature and connected to make one of said speed shift valves which establishes the highest speed stage incapable of establishing that highest speed stage when the engine temperature is below a predetermined value and to make said one speed shift valve capable of establishing the highest stage when the engine temperature is above a predetermined value.
Dependencies are inferred from the claim text.