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 automatic transmission of the present invention is provided with: a plurality of rotating shafts; a plurality of gears; a plurality of synchronizing mechanisms including an output-side synchronizing mechanism; a lubricating oil storage part that stores a lubricating oil which is drawn upward by rotation of the gears; a shift position detection unit that detects which of a plurality of shift positions, including a neutral position, has been selected; and a control unit which, if the neutral position has been detected by the shift position detection unit, causes a synchronizing mechanism other than the output-side synchronizing mechanism to operate, and brings a clutch into a connected state after coupling a rotating shaft other than an output shaft and a gear other than an output-side gear.

A modular design gearbox and a gear implementation method are provided. The gearbox includes a body, a drive shaft, four intermediate shafts, and an output shaft. The gearbox is of a six-shaft layout. The drive shaft S1, the intermediate shaft S4 and the intermediate shaft S5 are each provided with two clutch packs, and the intermediate shaft S2 is provided with one clutch pack. According to such a structure, a transmission path is short, and stability is better. By means of six shafts and seven clutches, the gearbox achieves a mode of up to eight forward gears and four backward gears, a speed ratio range is wide, and the gearbox can be adjusted flexibly, a less-gear mode can be achieved by reducing some of components, modularization is achieved, universality is improved, and the production cost and use cost of the gearbox are reduced.

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least eight forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and six selective couplers. The six selective couplers may include two clutches and four brakes.

A hybrid power system is provided having a motor, a double clutch, and a transmission with three synchronous meshing mechanisms, the hybrid power system can, through a reasonable structural design, implement the same as or more than the number of gears and operating modes of hybrid power systems employing a single motor and a dedicated hybrid transmission in the prior art, while being simpler in structure, more compact in size, and less costly.

A dual clutch transmission-equipped power unit includes a prime mover including a drive shaft and a dual clutch transmission that changes the speed of rotation produced by rotational power output by the drive shaft. The dual clutch transmission includes a first input shaft which overlaps the drive shaft when viewed in a first direction perpendicular to the drive shaft. The dual clutch transmission includes a second input shaft which overlaps the drive shaft when viewed in a second direction perpendicular to the drive shaft. The dual clutch transmission includes a countershaft which overlaps the drive shaft when viewed in a third direction perpendicular to the drive shaft.

An automatic transmission includes: a frictional engagement element including first and second annular friction plates; a pressing member moving in the axial direction relative to the transmission case and press the frictional engagement element in the axial direction; and a lubricating oil. Further, the transmission case includes a contact portion on the inner wall so that the contact portion is separated from a back surface of the pressing member when the frictional engagement element is in an engagement state and comes into contact with the back surface of the pressing member when the frictional engagement element is in a disengagement state.

An automatic transmission of the present invention is provided with: a plurality of rotating shafts; a plurality of gears; a plurality of synchronizing mechanisms including an output-side synchronizing mechanism; a lubricating oil storage part that stores a lubricating oil which is drawn upward by rotation of the gears; a shift position detection unit that detects which of a plurality of shift positions, including a neutral position, has been selected; and a control unit which, if the neutral position has been detected by the shift position detection unit, causes a synchronizing mechanism other than the output-side synchronizing mechanism to operate, and brings a clutch into a connected state after coupling a rotating shaft other than an output shaft and a gear other than an output-side gear.

A work vehicle includes an operation apparatus, a transmission having a plurality of gear positions, and a controller configured to control shift of a gear position of the transmission to a gear position equal to or lower than a shift upper limit position based on a vehicle speed of the work vehicle. The controller makes setting to raise the shift upper limit position by one position based on a first operation having been performed onto the operation apparatus. The controller changes the shift upper limit position from a first shift upper limit position immediately before a second operation different from the first operation to a second shift upper limit position based on the second operation having been performed onto the operation apparatus. The second shift upper limit position is higher than the first shift upper limit position by at least two positions.

A modular design gearbox and a gear implementation method are provided. The gearbox includes a body, a drive shaft, four intermediate shafts, and an output shaft. The gearbox is of a six-shaft layout. The drive shaft S1, the intermediate shaft S4 and the intermediate shaft S5 are each provided with two clutch packs, and the intermediate shaft S2 is provided with one clutch pack. According to such a structure, a transmission path is short, and stability is better. By means of six shafts and seven clutches, the gearbox achieves a mode of up to eight forward gears and four backward gears, a speed ratio range is wide, and the gearbox can be adjusted flexibly, a less-gear mode can be achieved by reducing some of components, modularization is achieved, universality is improved, and the production cost and use cost of the gearbox are reduced.