The present invention discloses a method for switching modes of an electromechanical transmission system which includes a clutch CL0, a motor A, a clutch CL1, a brake B1, a motor B and three planet rows K1, K2 and K3. The electromechanical transmission system according to the present invention achieves two different structural modes of EVT1 and EVT2 by changing states of the clutch CL0 and the brake B1. The EVT1 mode is mainly a system running state at a low vehicle speed under a high driving torque demand, and the EVT2 mode is mainly a system driving state at a high vehicle speed under a low driving torque demand. Mode switching without speed difference and power interruption can be achieved by switching vehicle speed selection and reasonable adjustment of engine and motor torque.

The present invention discloses a method for switching modes of an electromechanical transmission system which includes a clutch CL0, a motor A, a clutch CL1, a brake B1, a motor B and three planet rows K1, K2 and K3. The electromechanical transmission system according to the present invention achieves two different structural modes of EVT1 and EVT2 by changing states of the clutch CL0 and the brake B1. The EVT1 mode is mainly a system running state at a low vehicle speed under a high driving torque demand, and the EVT2 mode is mainly a system driving state at a high vehicle speed under a low driving torque demand. Mode switching without speed difference and power interruption can be achieved by switching vehicle speed selection and reasonable adjustment of engine and motor torque.

The disclosure provides a control device of an automatic transmission for vehicle, which can improve the responsiveness to switching to a reverse stage. The automatic transmission includes: planetary gear mechanisms which transmit the driving force input to an input shaft to an output member; and first to third clutches and first to fourth brakes as engagement mechanisms capable of establishing shift stages by switching a transmission path of the driving force in the planetary gear mechanisms. The control device executes a reverse preparation process for starting engagements of the first and third clutches and the third brake and stopping rotation of the input shaft when the reverse stage is selected when the fourth brake (mechanical engagement mechanism) is in a unidirectional rotation allowed state (first state) and the vehicle is traveling at a vehicle speed greater than a highest vehicle speed at which the reverse stage is establishable.

The disclosure provides a control device of an automatic transmission for vehicle, which can improve the responsiveness to switching to a reverse stage. The automatic transmission includes: planetary gear mechanisms which transmit the driving force input to an input shaft to an output member; and first to third clutches and first to fourth brakes as engagement mechanisms capable of establishing shift stages by switching a transmission path of the driving force in the planetary gear mechanisms. The control device executes a reverse preparation process for starting engagements of the first and third clutches and the third brake and stopping rotation of the input shaft when the reverse stage is selected when the fourth brake (mechanical engagement mechanism) is in a unidirectional rotation allowed state (first state) and the vehicle is traveling at a vehicle speed greater than a highest vehicle speed at which the reverse stage is establishable.

A dual-mode active rear-wheel steering device, including: a steering motor, a main shaft, an intermediate gear, a transmission gear, a planetary gear coupling mechanism and a mode switching assembly. An output end of the steering motor is provided with a first input gear. An end of the main shaft drives a first rear wheel to rotate by a two-stage gear transmission system and a first rear-wheel motion conversion mechanism, and the other end of the main shaft drives a second rear wheel to rotate by the planetary gear coupling mechanism and a second rear-wheel motion conversion mechanism. The intermediate gear, the transmission gear and a sun gear of the planetary gear coupling mechanism are provided on the main shaft. The intermediate gear meshes with the first input gear.

A dual-mode active rear-wheel steering device, including: a steering motor, a main shaft, an intermediate gear, a transmission gear, a planetary gear coupling mechanism and a mode switching assembly. An output end of the steering motor is provided with a first input gear. An end of the main shaft drives a first rear wheel to rotate by a two-stage gear transmission system and a first rear-wheel motion conversion mechanism, and the other end of the main shaft drives a second rear wheel to rotate by the planetary gear coupling mechanism and a second rear-wheel motion conversion mechanism. The intermediate gear, the transmission gear and a sun gear of the planetary gear coupling mechanism are provided on the main shaft. The intermediate gear meshes with the first input gear.

A four-speed transaxle for an electric vehicle comprises four planetary gear sets that is operatively connected to an electric motor, four electric caliper brake systems and one stage gears. The four-speed transaxle produces its first speed ratio when a first and third electric caliper brake systems are disengaged and a second and fourth electric caliper brake systems are engaged. Second speed ratio results when the first and fourth electric caliper brake systems are engaged and the second and third electric caliper brake systems are disengaged. Third speed ratio results when the second and third electric caliper brake systems are engaged and the first and fourth electric caliper brake systems are disengaged. Fourth speed ratio is produced when the first and third electric caliper brake systems are engaged and the second and fourth electric caliper brake systems are disengaged.

A four-speed transaxle for an electric vehicle comprises four planetary gear sets that is operatively connected to an electric motor, four electric caliper brake systems and one stage gears. The four-speed transaxle produces its first speed ratio when a first and third electric caliper brake systems are disengaged and a second and fourth electric caliper brake systems are engaged. Second speed ratio results when the first and fourth electric caliper brake systems are engaged and the second and third electric caliper brake systems are disengaged. Third speed ratio results when the second and third electric caliper brake systems are engaged and the first and fourth electric caliper brake systems are disengaged. Fourth speed ratio is produced when the first and third electric caliper brake systems are engaged and the second and fourth electric caliper brake systems are disengaged.

There is provided an automatic transmission capable of preventing deterioration of driving performance even when an engagement mechanism is not switched due to a failure. An automatic transmission includes a first brake which is always in a fixed state from a first forward gear stage to a predetermined gear stage and is in an open state at a gear stage with a higher speed than the predetermined gear stage, and a hydraulic sensor configured to detect whether the first brake is switched to the fixed state. When a transmission control device instructs the first brake to switch to the fixed state, and it is confirmed that the first brake is in an open state, the transmission control device instructs engagement mechanisms other than the first brake to perform switching so that a preliminary gear stage is able to be set.

A transaxle device (1) for a hybrid vehicle including an engine (2), a first rotating electric machine (3), and a second rotating electric machine (4) individually transmit the power of the engine (2) and power of the first rotating electric machine (3) to an output shaft (12) on a drive wheel side and also transmits the power of the engine (2) to the second rotating electric machine (4). Further, the transaxle device (1) includes an input shaft (11) which is coaxially connected to a rotating shaft (2a) of the engine (2) and a switching mechanism (20A) which is interposed in at least the input shaft (11) and switches a high gear stage (11H, 15H) and a low gear stage (11L, 15L).