Abstract: A power transmission mechanism for an automatic transmission, configured to establish seven or more forward speeds and one reverse speed. The power transmission mechanism includes four simple planetary gears, three connection members interconnecting two of the rotating members of the planetary gears, three clutches selectively connectable between two of the rotating members, and four brakes each operable to hold selectively against rotation one of the rotating members.

Abstract: A first planetary gear unit is arranged to convert an input rotation from an input shaft to an output rotation whose speed is lower than that of the input rotation. A first unit including second and third planetary gear units is arranged between the first planetary gear unit and the output shaft. The first unit manages the first planetary gear unit's output rotation and provides the output shaft with seven types of rotation which correspond to 6-forward speed and one reverse positions. A second unit is arranged between the first planetary gear unit and the first unit to manage a power transmission therebetween. One of the second and third planetary gear units is of a double ring type, each being meshed with the sun gear and inside and outside ring gears, and a pinion carrier carrying the pinions. The pinion carrier is connected to the output shaft to rotate therewith.

Abstract: A power transmission mechanism for an automatic transmission, configured to establish seven or more forward speeds and one reverse speed. The power transmission mechanism includes four simple planetary gears, three connection members interconnecting two of the rotating members of the planetary gears, three clutches selectively connectable between two of the rotating members, and four brakes each operable to hold selectively against rotation one of the rotating members.

Abstract: A first planetary gear unit is arranged to convert an input rotation from an input shaft to an output rotation whose speed is lower than that of the input rotation. A first unit including second and third planetary gear units is arranged between the first planetary gear unit and the output shaft. The first unit is arranged to provide, by managing the output rotation from the first planetary gear unit, the output shaft with seven types of rotation which respectively correspond to 6-forward speed and one reverse positions. A second unit is arranged between the first planetary gear unit and the first unit to manage a power transmission therebetween. One of the second and third planetary gear units is of a double ring type which comprises a sun gear powered by the first planetary gear unit, inside and outside ring gears concentrically disposed around the sun gear, pinions each being meshed with the sun gear and inside and outside ring gears, and a pinion carrier carrying the pinions.

Abstract: A vehicle power transmission device comprises a torque converter having an input member adapted to be connected with an engine output shaft and an output member, a multiple stage gear transmission mechanism, and a drive shaft having one end connected with the output member of the torque converter and passing through the gear mechanism. The gear mechanism includes a composite type planetary gear unit. A first clutch is provided and has a clutch drum connected with the drive shaft for connecting one gear unit element with the drive shaft through a one-way clutch, which permits power transmission from the drive shaft to the first sun gear. A second clutch is provided adjacent to the first clutch for connecting the drive shaft with the one element. A first brake is disposed with a brake drum around the second clutch and a brake band for frictional engagement with the brake drum. The first and second clutches can be arranged in the brake drum to provide a compact structure.

Abstract: A hydraulic control for an automatic transmission which comprises first and second friction coupling members, a first fluid passage for supplying an operating fluid for coupling the first friction coupling member, a second fluid passage for supplying an operating fluid for coupling the second friction coupling member, and an accumulator having a working chamber fluid-connected with the first fluid passage and comprising a piston and a spring for urging the piston in one direction. The piston is displaced against the spring, when the operating fluid is supplied into the working chamber, to regulate the pressure of the operating fluid for minimizing a shock resulting from the coupling of the first friction coupling members and also to open the second fluid pssage whereby the timing at which the second friction coupling member is coupled is delayed relative to the timing at which the first friction coupling member is coupled.