The biggest difference between the continuously variable transmission and the ordinary automatic transmission is that it eliminates the complicated and cumbersome gear combination transmission, and only uses two sets of pulleys for the transmission. By changing the contact radius of the drive wheel and the driven wheel drive belt to change the speed, its design concept is very clever. Because the CVT can realize the continuous change of the transmission ratio, so as to obtain the best match between the power train and the engine operating conditions, improve the fuel economy and power of the vehicle, improve the driver's convenience of operation and the riding comfort of the occupants, so it It is an ideal automobile transmission.
CVT sedans also have their own gears, such as parking gear P, reverse gear R, neutral gear N, forward gear D, etc., but when the car moves forward automatically, it is very stable and there is no sudden jump. Continuously variable transmission (CVT--continuously variable transmission), it does not have the gear transmission structure of the traditional gearbox, but uses two transmission wheels that can change the diameter, and the transmission belt is sleeved in the middle. The basic principle is to wind the two ends of the transmission belt on a tapered pulley, and the outer diameter of the pulley is steplessly changed according to the oil pressure. When starting off, the diameter of the driving pulley becomes the largest diameter, while the diameter of the passive pulley becomes the smallest, achieving a higher transmission ratio.
It does not have the gear transmission structure of the traditional gearbox inside, but is driven by two transmission wheels that can change the diameter, and the transmission belt is sleeved in the middle. The basic principle is to wind the two ends of the transmission belt on a tapered pulley, and the outer diameter of the pulley is steplessly changed according to the oil pressure. When starting, the diameter of the driving pulley becomes the smallest diameter, while the diameter of the passive pulley becomes the largest, achieving a higher transmission ratio. With the increase of vehicle speed and the change of each sensor signal, the computer control system determines the control oil pressure to control the two pulleys, and finally changes the continuous change of the diameter of the pulleys, so as to achieve stepless speed change in the whole speed change process.
In the past period of time, due to the material, the transmission belt between the tapered pulleys has limited tensile force and limited torque, so it can only be used on motorcycle-type small-displacement vehicles. In recent years, with the continuous improvement of material technology and processing technology, rigid drive belts and tapered pulleys made of special materials have been produced. Completely realize the high-power, high-torque car requirements.
The biggest feature of the hybrid planetary CVT is the stepless control of the output speed ratio, which achieves the feeling of flowing water while driving, so there is no feeling of shifting. The occupants do not feel the shift shock, and the power is connected and coherent. In this way, the CVT increases comfort while driving and accelerates faster than an automatic transmission.
Forcibly meshing two gears with different rotational speeds will inevitably cause impact collisions and damage the gears. When the first gear is to be shifted to the second gear, in order to reduce the impact, we commonly call it synchronizing. He has a coupling sleeve that first rubs against each other to synchronize, and then the gears are combined. That is, the inside of the lock ring is a cone, and the outside of the wheel at the gear position is also a cone. When they are combined, the braking force is generated and finally synchronized at a certain moment. Second and third gears are the same
The radius of gyration of the metal belt of the automotive lightweight product changes on the driving wheel set and the driven wheel set to realize the continuous change of the speed ratio. When the car starts, the working radius of the driving wheel is small, and the transmission can obtain a large transmission ratio, thereby ensuring that the drive axle can have enough torque to ensure that the car has a high acceleration. As the vehicle speed increases, the working radius of the driving wheel gradually decreases, the working radius of the driven wheel increases accordingly, and the transmission ratio of the CVT decreases, so that the car can travel at a higher speed.
