Hydraulic control device for automatic transmission for vehicle adapted to engage clutch at different speed according to engine output power
First Claim
1. In an automatic transmission for a vehicle such as an automobile having a speed stage shifting mechanism including parallelly arranged first and second hydraulically operated input clutches and adapted to provide a certain first speed stage in which said first and second input clutches are both engaged and a certain second speed stage higher than said first speed stage in which said first input clutch is disengaged and said second input clutch is engaged, the engagement of said first input clutch in said first speed stage being not essential unless engine brake availability is required,a hydraulic control device comprising a switching over valve variably operable according to an input signal representing engine output power so as to switch over supply of a hydraulic pressure to said first input clutch between a first mode of relatively slowly supplying said hydraulic pressure to said first input clutch and a second mode of relatively quickly supplying said hydraulic pressure to said first input clutch according to whether engine output power is higher than a determinate power level or less than said determinate power level, respectively.
1 Assignment
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Accused Products
Abstract
In an automatic transmission for a vehicle such as an automobile having a speed stage shifting mechanism including parallelly arranged first and second hydraulically operated input clutches and adapted to provide the 3rd speed stage in which the first and second input clutches C1 and C2 are both engaged (though the engagement of the clutch C1 in the 3rd speed stage is not essential unless engine brake availability is required) and the overdrive 4th stage in which the clutch C1 is disengaged and the clutch C2 is engaged, the clutch C1 in the 3rd speed stage being not essential unless engine a hydraulic control device has a switching over valve 330 for switching over supply of a hydraulic pressure to the first clutch C1 between a first mode of relatively slowing supplying the hydraulic pressure to the first clutch C1 and a second mode of relatively quickly supplying the hydraulic pressure to the first clutch C1 according to engine output power so as to select the second mode when engine output power is higher than a determinate power level as in the downshifting by kickdown and to select the first mode when engine output power is less than the determinate power level as in the overdrive inhibition.
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Citations
6 Claims
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1. In an automatic transmission for a vehicle such as an automobile having a speed stage shifting mechanism including parallelly arranged first and second hydraulically operated input clutches and adapted to provide a certain first speed stage in which said first and second input clutches are both engaged and a certain second speed stage higher than said first speed stage in which said first input clutch is disengaged and said second input clutch is engaged, the engagement of said first input clutch in said first speed stage being not essential unless engine brake availability is required,
a hydraulic control device comprising a switching over valve variably operable according to an input signal representing engine output power so as to switch over supply of a hydraulic pressure to said first input clutch between a first mode of relatively slowly supplying said hydraulic pressure to said first input clutch and a second mode of relatively quickly supplying said hydraulic pressure to said first input clutch according to whether engine output power is higher than a determinate power level or less than said determinate power level, respectively.
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5. In an automatic transmission for a vehicle such as an automobile having a speed stage shifting mechanism including parallelly arranged first and second hydraulically operated input clutches and adapted to provide a certain first speed stage in which said first and second input clutches are both engaged and a certain second speed stage higher than said first speed stage in which said first input clutch is disengaged and said second input clutch is engaged, the engagement of said first input clutch in said first speed stage being not essential unless engine brake availability is required,
a hydraulic control device fluidically connected to said first input clutch for supplying hydraulic pressure thereto, said hydraulic control device comprising a switch over valve having switch over means for switching between a first mode in which hydraulic pressure is slowly supplied to said first input clutch and a second mode in which hydraulic pressure is supplied to said first input clutch at a rate quicker than in said first mode, said switch over valve including means for receiving an engine output power signal, wherein said switch over means switches between said first and second modes as a function of a value of said engine output power signal such that said switch over valve is in said first mode when said engine output power signal is higher than a determinate value and in said second mode when said engine output power signal is lower than said determinate valve.
Specification