Calculation of the gearbox of the ZIL-130 car

2 Overview of vehicle transmission structures

2.1 Gearbox classification

The gearbox is designed to convert the torque and speed developed by the crankshaft of the engine to obtain various traction forces on the driving wheels when touching the car from its place and accelerating it, when driving the car and overcoming various road obstacles. The need for conversion is determined by the nature of the change in the ICE torque, the peculiarity of which is the relatively small adaptability to changes in external load.

Gearboxes according to the method of changing the gear ratio are divided into stepped, stepless and combined.

Stepped gearboxes by the number of forward stages are divided into three-, four-, five- and multi-stage, and by the position of the axes, into gearboxes with fixed shafts with rotating shafts (planetary) and combined. Gearboxes with fixed shafts are divided into two-, three- and multi-shaft gearboxes. According to the control method, transmissions can be with automatic, semi-automatic, pre-selector, command and direct control.

Speed gearboxes have high efficiency when transmitting full power. Speed gearboxes are characterized by simplicity of design at a lower cost compared to stepless ones. Therefore, they are widely used on cars of time-personal types

Calculation of the car checkpoint

3.1 Selection of kinematic diagram and material of gearbox parts

At the first stage of mechanical gearbox design, it is necessary to select the type of gearbox and determine its kinematic scheme. On cars with a front engine arrangement and with a rear driving axle, as a rule, three-shaft transmissions are used, on cars with a rear engine arrangement and on front-wheel drive cars - two-shaft. If there is an analogue car for the designed car, select the gearbox of the same type as the analogue

. The task of the developer will be significantly simplified if the kinematic scheme of the designed gearbox is similar to that of the analogue box. Kinematic diagrams of mechanical gearboxes of domestic cars and trucks are given in the source [1]. The selected kinematic diagram of the gearbox must be given in this subsection and the numbers of gearboxes of the gearbox corresponding to the gearbox number should be placed on it (with the sign "- for driving wheels and with the sign" - for driven ones). Here, it is also necessary to describe how the gears are implemented and to characterize the gears involved in the implementation of each gearbox transmission. For example:

1st gear-primary shaft of transmission of pair of helical gears of constant engagement (pz, pz) -

pair of spur gears of the first gear (1, "1") - secondary shaft of gearbox; and so on.

The dimensions of the gearbox and its durability are significantly influenced by the materials from which the gears and shafts of the gearbox are made. Gears of passenger car transmissions (module 3... 3.75) are usually made of chromium steels of 35X, 40X grades and subjected to cyanidation, while they have satisfactory hardenability and good strength. Chromomangan-titanium steels of 18ChGT, 25ChGT, 30ChGT grades are recommended for medium-module gearing of medium-capacity trucks. Steel 25HGM,20HNM, 12H3A is recommended to apply to krupnomodulny cogwheels with the subsequent cementation and training. Hardness of working surfaces of teeth of gears exceeds 56HRC. The above mentioned grades of alloyed steels are also used for the manufacture of gearbox shafts, and in order to reduce the range of materials used, the same grades of materials of gears and gearbox shafts are chosen .