摘    要

 
本设计是针对斯太尔重型车而进行的双级主减速器设计。此双级主减速器是由两级齿轮减速组成。与单级主减速器相比，双级减速器具有降低转速,增大扭矩的特点,在保证离地间隙相同时可得到很大的传动比，并且还拥有结构紧凑，噪声小，使用寿命长等优点。双级主减速器与单级相比，在保证离地间隙相同时可得到大的传动比，但是尺寸、质量均较大，成本较高。它主要应用于中、重型货车、越野车和大客车上
该设计包含了双级主减速器各零件参数的设计和校核。主要包括：主减速器结构的选择、主动锥齿轮传动比选择与齿轮设计、从动锥齿轮的设计、轴承的选择与校核，轴的选择与校核。在设计中，要选择正确的传动比以满足主从动锥齿轮的齿数分配，主减速器是汽车传动系中减小降低转速、增大扭矩的主要部件，它是依靠齿数少的锥齿轮带动齿数多的锥齿轮。对发动机纵置的汽车，其主减速器还利用锥齿轮传动以改变动力的方向。
 
 
 
关键词：载货汽车；双级主减速器；齿轮；校核；设计
                                                                                                                                           ABSTRACT
 
This design is designs a structure to the truck to be reasonable, work related reliable two-stage main gear box. This two-stage main gear box is composed of two level of gear reductions. Compares with the single stage main gear box, when the guarantee ground clearance is the same may obtain the very great velocity ratio, and also has the structure to be compact, the noise is small, service life long and so on merits.Two-stage main reducer and a single-stage than in the same ground clearance to ensure a large transmission ratio available, but the size, quality are larger, higher cost. It is mainly used in medium and heavy trucks, SUVs and buses on
 This article elaborated the two-stage main gear box each components parameter computation and the selection process, and through computation examination. The design mainly includes: Main gear box structure choice, host, driven bevel gear's design, bearing's examination. In the design, to select the correct gear ratio to satisfy the number of teeth of driving and driven bevel gear allocation The main reducer in the  transmission lines  used to reduce vehicle speed, increased the torque , it is less dependent on  the bevel of more gear drive of less bevel gear . Purchase of the longitudinal engine automobiles, the main bevel gear reducer also used to change the driving force for the direction of transmission.
 
 
 
Key words: Truck；Two-stage Main Reduction Gear；Gear；Check