Compact multi-ratio automatic transmission
OwnerErkki Koivuneninventor
Life of this patent
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Abstract
An automatic transmission for motor vehicles comprising three interconnected planetary gear units, two rotating friction clutches and four friction brakes providing six optimized forward gear ratios and a reverse ratio, all assembled into a compact package no larger than the current four-speed automatic transmissions. This invention preferably utilizes two multi-plate rotating clutches and special friction force balanced brake bands that allows self-synchronized ratio shifts without creating any side loading of associated band drums.
Claims13
A change ratio power transmission having an input member driven in a first rotary direction, a rotatable output member, a first planetary gearset having a sun gear and a ring gear and inner and outer planetary pinions operatively meshing with each other, said inner planetary pinions operatively mesh with said sun gear and said outer planetary pinions operatively meshing with said ring gear, a carrier for said inner and outer planetary pinions drivingly connected to said input member, a second planetary gearset having a sun gear and a ring gear and planetary pinions which mesh with said sun and ring gears thereof and a carrier for said last mentioned planetary pinions, a drive connection between said rings gear of said first and second planetary gearsets, a third planetary gearset having a sun gear and a ring gear and planetary pinions which mesh with said sun and ring gears thereof and a carrier for said planetary pinions of said third planetary gearset drivingly connected to said output member, a drive member operatively connecting said last mentioned sun gears for rotation together, a drive connection drivingly interconnecting said carrier of said second gearset to said ring gear of said third gearset, a first clutch selectively engageable for locking said first gearset for rotation as a unit, a second clutch selectively engageable for drivingly said carrier of said first gearset to the carrier of said second gearset a first brake selectively operable to simultaneously hold said sun gears of said second and third gearsets for reaction, a second brake for selectively holding said carrier of said second gearset for reaction and a third brake for selectively holding said ring gears of said first and said second gearsets for reaction and a fourth brake for selectively holding said sun gear of said first gearset for reaction.
A change speed power transmission for an automotive vehicle comprising rotatable input and output members, first, second and third planetary gearsets operatively connected in series to one another and operatively connecting said input member to said output member, said first planetary gearset having a sun gear and a ring gear and inner and outer planetary pinions that mesh with one another and arranged to operatively mesh with said sun and ring gears, said first gearset further having a carrier for said meshing planetary pinions, second and third planetary gearsets having sun and ring gears respectively and respectively having planetary pinions operatively interconnecting said associated sun and ring gears, second and third carriers for said planetary pinions of said second and third gearsets, said carrier of said first planetary gearset being connected directly to said input member, said carrier of said second gearset being connected to drive the ring gear of said third gearset and said carrier of said third gearset being connected to drive said output member, a first selectively engageable brake for holding said sun gear of said first gearset for reaction and a second selectively engagable brake for holding both of the sun gears of said second and third planetary gearsets for reaction so that said drive ratio of said first gearset thereby established is further multiplied by said drive ratio of said second gearset and that is further multiplied by the drive ratio of the third gearset to thereby establish a first torque increasing and speed reducing input/output member drive ratio.
A change speed power transmission for an automotive vehicle comprising rotatable transmission imput and output members, first, second and third planetary gearsets operatively connected in series to one another and operatively connecting said input member to said output member, said first of said planetary gearsets being a double pinion planetary gearset having a sun and a ring gear operatively interconnected by said double pinion planet gears and a carrier for said double pinion planetary gears, said second and third planetary gearsets each having planet gears meshing with said associated sun and ring gears, and second and third carriers for said planetary gears, said carrier of said first planetary gearset being directly connected to said input member, said carrier of said second planetary gearset being connected to drive the ring gear of said third gearset and said carrier of said third planetary gearset being the output of all of said planetary gearsets and being directly connected to drive said output member, a first brake selectively engagable for holding said sun gears of said second and third planetary gearsets for reaction so that a first speed ratios is established with the ratio of said first gearset being multiplied in series by the established ratios of said second and said third gearsets.
A change ratio transmission for an automatic transmission for a vehicle comprising rotatable power input and output members, first, second and third planetary gearsets operatively connected to one another and operatively connecting said input and said output member, said first planetary gearset being a double pinion planetary gearset and said second and third planetary gearsets being simple planetary gearsets, said double pinion planetary gearset having a carrier directly connected to said input member and having a ring gear directly connected to said ring gear of said second planetary gearset, said second and third planetary gearsets having sun gears directly connected to one another, said carrier of said second planetary gearset being connected to said ring gear of said third planetary gearset, said carrier of said third gearset being drivingly connected to said output member, a first selectively engageable brake for holding said sun gears of said simple planetary gearsets for reaction, a second selectively engageable brake for holding said carrier of said second planetary gearset and said ring gear of said third gearset for reaction, a third selectively engageable brake for holding said ring gears of said first and second planetary gearsets in reaction, a fourth selectively engageable brake for holding said sun gear of said first and second planetary gearsets for reaction, a first selectively engageable clutch for drivingly connecting said sun gear to said carrier of said first planetary gearset to effect a lock-up of said first planetary gearset, a selectively engageable clutch for drivingly connecting said input to said carrier of said second planetary gearset, wherein (1) application of said first and fourth brakes establishes a first drive ratio, (2) application of said first brake and said first clutch establishes a second drive ratio, (3) application of said first brake and said second clutch establishes a third drive ratio and application of said first and second clutches locks up said gearset to establish a direct drive ratio.
Dependencies are inferred from the claim text.