The present invention discloses a six-gear automatic transmission for automobile with a brushless control-by-wire centrifugal ball arm engagement device. One brushless control-by-wire centrifugal ball arm engagement device is provided between each gear input gear and each gear driving gear; and by controlling the engagement and disengagement of the brushless control-by-wire centrifugal ball arm engagement device, the shifting control of the six-gear automatic transmission for automobile with a brushless control-by-wire centrifugal ball arm engagement device is performed. The present invention has such advantages as compact structure, being capable of dynamic gear-shift, no mechanical or hydraulic gear-shift components and low operational energy consumption.

An actuator system has a power source, an output member, a first fluidic coupling and a second fluidic coupling. The fluidic couplings generate a variable amount of torque transmission. A transmission operatively couples the fluidic couplings to the power source and to the output member in at least first load path and a second load path, the first load path and the second load path being parallel to one another, the first load path including the first fluidic coupling, the second load path including the second fluidic coupling. The fluidic couplings are operable for torque from the power source to be transmitted solely via the first load path, solely via the second load path, and cumulatively via the first load path and the second load path.

A control system for an engagement device that engage the engagement device promptly to reduce a power loss is provided. The control system has a controller configured to start controlling a first motor in such a manner as to synchronize a rotational speed of a first engagement element to a rotational speed of a second engagement element, simultaneously with a commencement of engagement of the first engagement element with the second engagement element, or after the commencement of the engagement of the first engagement element with the second engagement element.

A method for power transmission method includes providing first and second shafts, first and second gear assemblies between the first and second shafts, and first and second coupling assemblies. The first coupling assembly coupling the first shaft to the first gear assembly, and the second coupling assembly coupling the first shaft to the second gear assembly. The speed of the first shaft varies, wherein the deployment of a locking element of the second coupling assembly is based on the speed of the first shaft.

A method for power transmission method includes providing first and second shafts, first and second gear assemblies between the first and second shafts, and first and second coupling assemblies. The first coupling assembly coupling the first shaft to the first gear assembly, and the second coupling assembly coupling the first shaft to the second gear assembly. The speed of the first shaft varies, wherein the deployment of a locking element of the second coupling assembly is based on the speed of the first shaft.

A method for power transmission method includes providing first and second shafts, a gear assembly having first and second gear ratios, and first and second coupling assemblies. The first coupling assembly enabling torque transfer from the first shaft to the second shaft, and the second coupling assembly enabling torque transfer from the first shaft to the second shaft. The speed of the first shaft varies, wherein the deployment of a locking element of the second coupling assembly is based on the speed of the first shaft.

A transmission structure of a mid-drive motor has a shell, an output axle, a motor unit, and a clutch assembly. The clutch assembly has a driving ring, a clutch gear, an output gear, and a pressing device. The driving ring is connected to the motor unit. The output gear is connected to the output axle and is detachably connected to the clutch gear. The pressing device has a base casing, a pressing disc, and an elastic unit. The pressing disc moves axially in the base casing, and the elastic unit abuts the pressing disc and the base casing. The clutch gear drives the pressing disc to rotate, and the pressing disc pushes the clutch gear to engage with the output gear. The elastic unit and the pressing device reset the pressing disc, and the pressing device resets the clutch gear after the clutch gear separating from the output gear.