Planetary gear type multistage transmission for vehicle

A vehicular planetary gear type step-variable transmission comprising:

• a first transmission portion and a second transmission portion which are disposed coaxially with a first axis, and wherein a rotary motion of an input rotary member rotated by a drive power source about the first axis is transmitted from said first transmission portion to said second transmission portion through a first intermediate output path, and a second intermediate output path a rotation motion of which is decelerated with respect to the rotary motion of said input rotary member at a speed ratio higher than that of said first intermediate output path, and a rotary motion of an output rotary member rotated about said first axis is transmitted to a drive wheel of a vehicle;
• said first transmission portion including a first planetary gear set of a double-pinion type having a first carrier connected to said input rotary member and said first intermediate output path, a first ring gear connected to said second intermediate output path, and a first sun gear fixed to a stationary member;
• said second transmission portion including a second planetary gear set of a single-pinion type having a second sun gear, a second carrier and a third ring gear, and a third planetary gear set of a double-pinion type having a third sun gear, a third carrier and a third ring gear, said first sun gear being selectively connected through a fourth clutch to said first intermediate output path, selectively connected through a third clutch to said second intermediate output path, and selectively fixed through a first brake to said stationary member, said second carrier and said third carrier being constituted by a common member, selectively connected through a second clutch to said first intermediate output path, and selectively fixed through a second brake to said stationary member, said second ring gear and said third ring gear being constituted by a common member and fixed to said output rotary member, and said third sun gear being selectively connected through a first clutch to said second intermediate output path;
• and
• a power transmitting member is disposed rotatably about a second axis parallel to said first axis and operatively connected to said output rotary member, for transmitting the rotary motion of said output rotary member to said drive wheel,
• said vehicular planetary gear type step-variable transmission being installed on the vehicle such that said first axis and said second axis are parallel to a width direction of the vehicle.

A vehicular planetary gear type step-variable transmission comprising:

• a first transmission portion and a second transmission portion which are disposed coaxially with a first axis, and wherein a rotary motion of an input rotary member rotated by a drive power source about the first axis is transmitted from said first transmission portion to said second transmission portion through a first intermediate output path, and a second intermediate output path a rotation motion of which is decelerated with respect to the rotary motion of said input rotary member at a speed ratio higher than that of said first intermediate output path, and a rotary motion of an output rotary member rotated about said first axis is transmitted to a drive wheel of a vehicle;
• said first transmission portion including a first planetary gear set of a double-pinion type having a first carrier connected to said input rotary member and said first intermediate output path, a first ring gear connected to said second intermediate output path, and a first sun gear fixed to a stationary member;
• said second transmission portion including a second planetary gear set and a third planetary gear set each of which has a sun gear, a carrier and a ring gear, and having four rotary elements each of which is provided by one member or a combination of a plurality of connected members selected from among said sun gears, said carriers and said ring gears of said second and third planetary gear sets, said four rotary elements having respective rotating speeds that are represented along respective four straight lines in a collinear chart, which four straight lines are arranged in a direction from one of opposite ends of the collinear chart toward the other end, said first rotary element being selectively connected through a fourth clutch to said first intermediate output path selectively connected through a third clutch to said second intermediate output path, and selectively fixed through a first brake to said stationary member, said second rotary member being selectively connected through a second clutch to said first intermediate output path, and selectively fixed through a second brake to said stationary member, said third rotary element being fixed to said output rotary member, and said fourth rotary member being selectively connected through a first clutch to said second intermediate output path;
• a power transmitting member is disposed rotatably about a second axis parallel to said first axis and operatively connected to said output rotary member, for transmitting the rotary motion of said output rotary member to said drive wheel;
• said vehicular planetary gear type step-variable transmission being installed on the vehicle such that said first axis and said second axis are parallel to a width direction of the vehicle;
• said first planetary gear set, said second planetary gear set and said third planetary gear set being disposed in this order of description, coaxially with said first axis;
• and
• said fourth clutch being disposed on one side of said first planetary gear set which is remote from said second planetary gear set, and being connected to said first carrier.

The vehicular planetary gear type step-variable transmission according to claim 14, which has a plurality of gear positions selected from among:

• a first gear position which is established by engaging said first clutch and said second brake or a one-way clutch and which has a highest speed ratio;
• a second gear position which is established by engaging said first clutch and said first brake and which has a speed ratio lower than that of said first gear position;
• a third gear position which is established by engaging said first clutch and said third clutch and which has a speed ratio lower than that of said second gear position;
• a fourth gear position which is established by engaging said first clutch and said fourth clutch and which has a speed ratio lower than that of said third gear position;
• a fifth gear position which is established by engaging said first clutch and said second clutch and which has a speed ratio lower than that of said fourth gear position;
• a sixth gear position which is established by engaging said second clutch and said fourth clutch and which has a speed ratio lower than that of said fifth gear position;
• a seventh gear position which is established by engaging said second clutch and said third clutch and which has a speed ratio lower than that of said sixth gear position;
• and
• an eighth gear position which is established by engaging said second clutch and said first brake and which has a speed ratio lower than that of said seventh gear position.