2-Speed eAD Transmission

According to the design of EV 2-speed gearbox, there is an extra gear ratio to shift the gears. The different gear ratio will affect the performance of motor and energy efficiency. The user can change the gears depends on road conditions to improve endurance and maneuverability.

The design of the EV gearbox is easier than the traditional fuel vehicle. The enhancement of motor also perform well at high/low speed without more shift gear. For last years, all the EV suppliers dedicate to increase the endurance for electric vehicle. There is almost 4.3% for improving energy benefit by NEDC simulation result for our 2-speed gearbox. Until now, we still keep studying for improving proposal.

The supplier will provide the basic specification for selection. In addition to match the external dimensions, the key point as below item.
I.The input torque(Maximum/Rated) from motor
II.The input rotating speed(Maximum/Rated) from motor
III.Center distance between the location of input and output
IV.Lubrication method/the kind of lubrication
V.Parking and shifting mechanisms
VI.The Layout of the vehicle

We will provide the drawing for customer to see if flange size and assembly position can match. If it is incompatible, you may have to modify.

When the gear was rotated by motor, the gear splash the engine oil. Then, lubricating all gears and form the oil film over the gear surface.

The shape of gearbox case is usually irregular. We used to use grey cast iron as material because it can reduce vibration and costs. We have focused on lightweight gearbox recently so aluminum alloy has replaced as the main material. You can see aluminum alloy die casting on the market.

The temperature depends on the design and the condition of oil. High temperature will have property change so the temperature of the gearbox used in vehicles should not exceed 90 degrees.

You have to check the location of the gearbox on the vehicle, the condition of transmission and the direction of vehicle travel first. For instance, the input shaft is clockwise and it’s the same as the output shaft.

Base on design of the EV gearbox and keep motor performance
According to F=ma, the higher output torque can bring higher acceleration to the vehicle. You can enlarge the gear ratio to have higher acceleration.

The noise of the gearbox of electric vehicles is lower than the fuel vehicles. We focus on solving the noise of the gearbox, so we get on with improving gear precision, controlling the manufacturing process, and reducing human error.

The reason for the noise of the gearbox is the combined results of all internal and external conditions. At this stage, it is difficult to attribute the noise to a single cause. The external cause may be the locking condition of the engine foot, the mounting design of the gearbox. For Internal, causes may be damage to mechanism components, wrong assembly conditions. In addition to the items mentioned above, the resonance conditions by the gearbox must be considered.

Our 1-speed gearbox is about 30kilograms/66.1 pounds(with oil), and 2-speed is about 45kilogram/99.2pounds(with oil).

We assume that there will be driving gear (number of teeth = 20T) and a driven gear (number of teeth = 40T) , the gear ratio is 1:2. While the two gears are meshing, it can be calculated from dividing the driven gear by the driving gear. The second-stage gear transmission is multiplied sequentially to get the final gear ratio.