A seal structure between an oil outlet formed in a first case and an oil inlet formed in a second case and having an end face facing an end face of the oil outlet with a clearance between the end faces, the seal structure including an annular first seal disposed in an increased-diameter hole, which is formed on an outlet side or an inlet side of an oil passage in one of the oil outlet and the oil inlet and has a larger diameter than the oil passage, such that the first seal contacts a step surface located at a boundary between the oil passage and the increased-diameter hole; and an annular second seal harder than the first seal and disposed in the increased-diameter hole such that the second seal contacts the first seal and the end face of the other of the oil outlet and the oil inlet.

Disclosed is a method for operating a multi-gear vehicle transmission having a plurality of shifting elements (A, B, C, D, E) for engaging the gears of the vehicle transmission, where, in a neutral gear an input (AN) and an output (AB) of the vehicle transmission are decoupled from one another, and where, in a driving gear the input (AN) and the output (AB) of the vehicle transmission are coupled to one another in order to propel the vehicle, by closing at least one shifting element (B). When the neutral gear is engaged, at least an actuation condition of a vehicle brake (11) and a transmission condition with elevated drag losses are detected, where, when the neutral gear is engaged, the shifting element (B) for the driving gear is vented if it is recognized that the vehicle brake (11) has been released and the transmission condition with elevated drag losses pertains.

A method is disclosed for operating a multi-gear vehicle transmission in a motor vehicle during a coasting phase. The coasting phase includes an overrun phase with a driving gear engaged and a freewheeling phase with the neutral gear engaged. It is determined whether the motor vehicle is in the overrun phase of the coasting phase, whether a condition for a transition to the freewheeling phase of the coasting phase is fulfilled, and whether a transmission condition with elevated drag losses exists. If the motor vehicle is in the overrun phase of the coasting phase, if the condition for transition to the freewheeling phase is fulfilled, and if a transmission condition with elevated drag losses exists, then at least one further shifting element (D, E) is closed in addition to the shifting elements (A, B, C) of the driving gear, which are closed during the overrun phase of the motor vehicle.

Disclosed is a method for operating a multi-gear vehicle transmission having a plurality of shifting elements (A, B, C, D, E) for engaging gears of the vehicle transmission. In a neutral gear, in which some of the shifting elements (A, B) are already actuated, a transmission input (1) is decoupled from a transmission output (2) of the vehicle transmission. In a driving gear the transmission input (1) is coupled to the transmission output (2) of the vehicle transmission by closing the shifting elements (A, B, C, D, E) associated with the driving gear, in order to propel the vehicle. With the neutral gear engaged a transmission condition is determined, and if a transmission condition with elevated drag losses exists, then in addition to the shifting elements (A, B) actuated in the neutral gear a shifting element (D) associated with a reversing gear of the vehicle transmission is also closed.

A gearbox comprising: an outer intermediate shaft carrying a first set of shaft gears; an inner intermediate shaft carrying a second set of shaft gears, the inner intermediate shaft running concentrically within the outer intermediate shaft; a first lay shaft carrying a first set of drive gears and an output gear positioned along the first lay shaft between two of the first set of drive gears, a second lay shaft carrying a second set of drive gears and an output gear positioned along the second lay shaft between two of the second set of drive gears, each drive gear being coupled to a respective shaft gear to together provide a plurality of gear ratios between the intermediate shafts and the output shaft; and an output shaft, each lay shaft being coupled to the output shaft by the respective output gear.

An alternative braking apparatus for a vehicle includes a gear type automatic transmission having at least one clutch and at least one brake for changing the meshing state of gears, and a control unit configured to switch the shift stage of the automatic transmission by controlling the clutch and the brake. The control unit is configured to perform alternative braking that controls the clutch and the brake so that an output shaft of the automatic transmission is braked by a braking force of the brake through the gears when the control unit determines that a braking device of the vehicle cannot normally apply braking forces to wheels despite that the vehicle needs to be braked.

An automatic transmission includes a brake including a fixed-side cylindrical member spline-coupled to a transmission case, a rotation-side cylindrical member coupled to a given rotating member, a plurality of friction plates disposed between the fixed-side cylindrical member and the rotation-side cylindrical member, and including a fixed-side friction plate configured to be spline-engaged with the fixed-side cylindrical member and a rotation-side friction plate configured to be spline-engaged with the rotation-side cylindrical member, and a piston configured to engage the plurality of friction plates. The automatic transmission further includes a shock absorbing member disposed between a spline part of the transmission case and a spline part of the fixed-side cylindrical member and configured to absorb impact when the fixed-side cylindrical member rotates relative to the transmission case.

A plug-in hybrid powertrain for automotive vehicle is provided which has an internal combustion engine; an electric machine; multiple planetary gear sets, multiple selectively engageable clutch mechanisms and an output member. Selectively engaging those clutches will achieve multiple operation modes including multiple torque transfer ratio from electric machine to output member; multiple torque transfer ratio from internal combustion engine to output member; electric machine propulsion mode; internal combustion engine propulsion mode; generator assistant vehicle launch modes for forward and reverse in the internal combustion engine vehicle launch operations; motor assistant propulsion when in internal combustion engine vehicle propulsion operations; and engine cranking mode. The plug-in hybrid powertrain achieves more torque transfer ratios and operational mode with given number of planetary gear sets and clutches then any existing system.

A gearbox comprising: an outer intermediate shaft carrying a first set of shaft gears; an inner intermediate shaft carrying a second set of shaft gears, the inner intermediate shaft running concentrically within the outer intermediate shaft; a first lay shaft carrying a first set of drive gears and an output gear positioned along the first lay shaft between two of the first set of drive gears, a second lay shaft carrying a second set of drive gears and an output gear positioned along the second lay shaft between two of the second set of drive gears, each drive gear being coupled to a respective shaft gear to together provide a plurality of gear ratios between the intermediate shafts and the output shaft; and an output shaft, each lay shaft being coupled to the output shaft by the respective output gear.

The invention relates to a dual clutch transmission (11, 211, 411, 611), comprising a gear-change transmission (15, 215, 415, 615) for forming eight gear steps having two countershafts (29, 31, 229, 231, 429, 431, 629, 631, 829) and having a common output shaft (33, 233, 433, 633). Said dual clutch transmission is configured in such a way that all gear steps are designed as forward gears. Hereby, a double clutch (13, 213, 413,613) has two clutch packs (17, 19, 219, 417, 419, 617, 619) arranged on a central axis (23, 223, 423, 623) of the double clutch transmission. A drive input shaft (21, 221, 421, 621) of the dual clutch transmission is seated on the central axis (23, 223, 423, 623), on which drive gearwheels (41, 241, 441, 641; 43, 243, 443, 643; 45, 245, 445, 643; 47, 247, 447, 647; 49, 249, 449, 649; 51, 251, 451, 651) of the individual gear steps are seated.