Seven-gear speed changing box

Abstract

The invention discloses a seven-gear speed changing box. The seven-gear speed changing box comprises a first speed changer shaft, a second speed changer shaft and a middle speed changer shaft. A first shaft gear is connected with the first speed changer shaft through an inner spline, and a second shaft gear and a synchronizer are connected with the second speed changer shaft through inner splines; and a front-segment middle shaft is sleeved with the middle shaft gear, and relative rotation between the middle shaft and the middle shaft gear is avoided through a square key. It is ensured that a structure of a shell is not changed, the synchronizer can sufficiently transmit needed torque, and on the premise that the bending strength and the contact fatigue strength of the gears meet the requirement of the service life, a force transmission structure of speed changers is designed, and conditions needed by a pump truck driving condition and a pump material working condition are met. Tooth parameters are adjusted, the axial width of gear distribution is optimized, and therefore the gears can meet the requirement of strength and the speed ratio, and the problem of limitation of the axial size can be solved. Meanwhile, the rated input torque can be increased; and through design of a single box, phenomena of tooth beating, difficult gear engaging and the like generated by simultaneous gear engaging of a main box and an auxiliary box are avoided.

Description

【Technical field】 [0001] The invention belongs to the technical field of automobile transmissions, and relates to a 7-speed gearbox. 【Background technique】 [0002] Pump trucks are a common model in the field of commercial vehicles. At present, the pump truck products of domestic manufacturers such as Sany and Zoomlion are all equipped with imported Volvo, Mercedes-Benz and other brand transmissions. The price accounts for a very important part of the product cost, which leads to the high price of the pump truck. [0003] Most of the existing pump truck transmissions in China have a combination structure of main and auxiliary boxes. According to the survey, the transmission with this structure will often cause the main box to start shifting gears before the auxiliary box completes the gear shifting process due to the slow shifting speed of the auxiliary box, resulting in tooth grinding, difficulty in shifting gears, or even failure to shift gears. Phenomenon. In order to...

AI Technical Summary

Problems solved by technology

However, due to the harsh working environment of the pump truck and the short service life of air pipes and other components, the sealing performance of the interlock air circuit cannot be guaranteed, which in turn leads to the failure of the interlock mechanism and the failure to achieve the purpose of interlocking the main and auxiliary tanks

[0004] In addition, the maximum rated input torque of the 7-speed transmission on the market is 1800Nm, which cannot meet the market demand for increasing engine power, nor can it adapt to the working conditions of pump trucks that require high input torque.

Images