A transaxle comprises first and second input shafts coaxial to each other, an output shaft drivingly connected to the second input shaft, a torque limiter interposed between the first and second input shafts, and a housing incorporating the first and second input shafts, the output shaft and the torque limiter. The torque limiter includes first and second sleeves. The first sleeve is fitted to the first input shaft unrotatably relative to the first input shaft. The second sleeve is fitted to the second input shaft unrotatably relative to the second input shaft. The first and second sleeves are layered in a radial direction of the first and second input shafts so as to be pressed against each other with a radial surface pressure to limit a torque transmitted between the first and second sleeves to a limiting value.

A transaxle comprises first and second input shafts coaxial to each other, an output shaft drivingly connected to the second input shaft, a torque limiter interposed between the first and second input shafts, and a housing incorporating the first and second input shafts, the output shaft and the torque limiter. The torque limiter includes first and second sleeves. The first sleeve is fitted to the first input shaft unrotatably relative to the first input shaft. The second sleeve is fitted to the second input shaft unrotatably relative to the second input shaft. The first and second sleeves are layered in a radial direction of the first and second input shafts so as to be pressed against each other with a radial surface pressure to limit a torque transmitted between the first and second sleeves to a limiting value.

Disclosed are a parallel start control method and system for a hybrid electric vehicle, and a hybrid electric vehicle. The parallel start control method includes: acquiring current working conditions of a clutch and a gearbox of the hybrid electric vehicle, an engine request torque of the hybrid electric vehicle and a start mode of the hybrid electric vehicle; judging whether the hybrid electric vehicle meets an over-heat protection condition according to the current working conditions of the clutch and the gearbox and determining a start basic torque according to a judging result and the engine request torque; determining a start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle and conducting start control on the clutch according to the start clutch request torque. The start security, responsiveness and power performance of the hybrid electric vehicle are improved.

A power transmission unit that can prevent an entrance of excessive torque to the powertrain is provided. The power transmission unit includes a transmission that transmits torque between an engine and drive wheels; a locking device that selectively halts a rotation of an output shaft of the engine; a transmission case holding a first motor, a second motor, the transmission, and the locking device; a first torque limiter disposed between the engine and the locking device to restrict torque transmitted between the drive wheels and the engine; and a second torque limiter held in the transmission case to restrict torque transmitted between the drive wheels and the locking device.

A power transmission unit that can prevent an entrance of excessive torque to the powertrain is provided. The power transmission unit includes a transmission that transmits torque between an engine and drive wheels; a locking device that selectively halts a rotation of an output shaft of the engine; a transmission case holding a first motor, a second motor, the transmission, and the locking device; a first torque limiter disposed between the engine and the locking device to restrict torque transmitted between the drive wheels and the engine; and a second torque limiter held in the transmission case to restrict torque transmitted between the drive wheels and the locking device.

Disclosed are a parallel start control method and system for a hybrid electric vehicle, and a hybrid electric vehicle. The parallel start control method includes: acquiring current working conditions of a clutch and a gearbox of the hybrid electric vehicle, an engine request torque of the hybrid electric vehicle and a start mode of the hybrid electric vehicle; judging whether the hybrid electric vehicle meets an over-heat protection condition according to the current working conditions of the clutch and the gearbox, and determining a start basic torque according to a judging result and the engine request torque; determining a start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle; and conducting start control on the clutch according to the start clutch request torque. The start security, responsiveness and power performance of the hybrid electric vehicle are improved.