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US 5,203,234 AGranted
Automatic transmission
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsToshiyuki Asada, Yasuo Hojo, Hideo Tomomatsu
Life of this patent
Estimating the term…
Abstract
An automatic transmission which includes a device for selecting and temporarily setting such one of other speed stages, if any, between a present speed stage and a target speed stage as can have a small number of fluctuating revolutions of rotary members of planetary gear sets of the automatic transmission and two or less frictional engagement elements to be switched.
Claims21
An automatic transmission for a vehicle, comprising:
- a gear train comprising a plurality of planetary gear sets each having rotary members;
- a plurality of frictional engagement means for setting a plurality of main speed stages through which drive force is transmitted during running of the vehicle, and auxiliary speed stages having a gear ratio of an intermediate value between those of said main speed stages, which are not selected based on the engine load, by connecting or stopping the rotary members of said planetary gear sets to change the transmission path of the drive force through said gear train;
- hydraulic control means for changing the engagement/release statuses of said frictional engagement means;
- shift decision means for deciding a shift from one of said main speed stages to another main speed stage;
- auxiliary speed stage selection means for selecting at least one auxiliary speed stage between said main speed stages;
- and
- output means for outputting an instruction signal to said hydraulic control means as to shift from said one main speed stage to said another main speed stage and so as to set said at least one auxiliary speed stage temporarily at the time of the shift between said main speed stages, wherein said at least one auxiliary speed stage is selected such that the revolving, direction of the rotary members of said planetary gear sets is not reversed during the shift between said main speed stages.
4 more elements
An automatic transmission comprising:
- a gear train comprising a plurality of planetary gear sets each having rotary members;
- a plurality of frictional engagement means for setting a plurality of speed stages by either connecting the rotary members of said planetary gear sets or stopping the revolutions of said rotary members to change the transmission path of a drive force through said gear train;
- hydraulic control means for changing the engagement/release statuses of said frictional engagement means;
- shift decision means for deciding a shift from one of said speed stages to another;
- intermediate stage selection means for selecting an intermediate speed stage between said plurality of speed stages, in which the one of the speed stages and another are apart two or more stages from each other, based upon consideration of the number of said frictional engagement means and the number of fluctuating revolutions of the rotary members of the planetary gearsets which changes the engagement/release statuses substantially simultaneously;
- and
- output means for outputting an instruction signal to said hydraulic control means as to set said intermediate speed stage temporarily at the time of the shift between said plurality of speed stages.
4 more elements
An automatic transmission for a vehicle comprising:
- a gear train comprising a plurality of planetary gear sets each having rotary members;
- a plurality of frictional engagement means for setting a plurality of speed stages by either connecting or stopping the rotary members of said planetary gear sets to change the transmission path of a drive force through said gear train;
- hydraulic control means for changing the engagement/release statuses of said frictional engagement means;
- shift decision means for deciding a shift from one of said speed stages to a target speed stage which is apart three or more stages from said one of the speed stages;
- intermediate stage selection means for selecting an intermediate speed stage of a lower gear ratio between said one of the speed stages and the target speed stage, in case a shift is an upshift, and an intermediate speed stage of a higher gear ratio between said one of the speed stages and the target speed stage in case said shift is a downshift;
- and
- output means for outputting an instruction signal to said hydraulic control means as to set said intermediate speed stage temporarily at the time of the shift between said plurality of speed stages.
4 more elements
Dependencies are inferred from the claim text.