1. It is straight tooth sliding gear shifting, and directly operating the gear to make it combine; 2. Synchronizer shifting, that is to say, the friction of synchronizer makes the linear speed of shifting gears keep the same, and then complete easy shifting; 3. Power shift: through a series of clutch and friction plate control (control method is hydraulic control) to achieve easy shift; 4. CVT shift skills: and the so-called infinite speed change skills, through the belt or chain transmission, complete the change of vehicle speed.

1. The average power is increasing. In order to improve the production rate of single machine, the average power of agricultural and industrial machines has been increasing, but the growth rate has been declining.

2. In the agricultural extension machine, the wheel extension machine is dominant. In many countries agricultural production has basically not used crawler extension machine. In order to improve the traction and adhesion performance and passing capacity in paddy field, the four-wheel drive variant of medium and small power wheel tractor has also been developed rapidly in Japan and other countries.

3. More and more attention has been paid to the safety, ease of operation and comfort of working environment. Planning and making a good cab and various appearances can not only improve the driver's working conditions and ensure safety, but also improve labor productivity and operation quality.

4. The serialization, generalization and standardization of the extension machine and its parts are important measures to facilitate production, use, reduce production costs and simplify the supply of accessories. Increase the production volume of general parts; Or it can produce similar parts in the same processing line, and assemble similar parts and adjacent grade extension machines in the same assembly line. This is very beneficial to make full use of production capacity and reduce production costs.

5. Hydraulic technology is widely used in the extension machine. In modern procrastination machine, especially in large procrastination machine, almost all the primary components are operated by hydraulic equipment, such as clutch, power shift of gearbox, differential lock, brake and steering mechanism. On some extension machines, hydraulic equipment is also used for seat adjustment and glass window opening and closing. The suspension system controlled by electronic hydraulic system has been used in some extenders. Because of the convenience of the arrangement of the operation switches, the hydraulic pipeline can be shortened correspondingly, and it will be more widely used in large extenders.

6. Some components of the machine will bear random alternating load for a long time, which will cause fatigue damage and affect the working reliability and life of the machine. This can not only improve the product quality, but also shorten the research and development cycle of new products. Advanced extension machine manufacturers have applied computer aided planning (CAD) means for product planning. More and more attention has been paid to the research and application of optimal planning.