Heading work on machine parts drive plate conveyor

2.2.2 Selection of workpiece

Rolling billets are used to make the shaft from 35CM steel.

Shafts are made of rolled stock by free forging on a hammer.

Forging and stamping technology consists in the following:

a) heat to forging temperature Tnagr = 1260 ° С, Tco = 800 ° С;

b) calibrate forging in die;

c) cool to shop temperature.

In order to obtain a forging of high quality, it is necessary that the microstructure of the metal be fine-grained, so that the specified forging temperature intervals must be strictly observed.

After forging, it is necessary to carry out preliminary heat treatment to correct the structure and final heat treatment to obtain the necessary strength properties of the steel.

Selection of process equipment

Selection of equipment for preliminary and final heat treatment is performed from Table 11. We choose the average temperature furnace of SN3,6,5.5.2/10 grade and the low temperature furnace of SN3.6,5.2/7 grade.

Decryption of furnace index: C - resistance heating, H - heating chamber, H or O - protective or oxidizing atmosphere. Numbers after letters: in the numerator - the width, length and height of the working space in dm, in the denominator - the maximum working temperature in hundreds of degrees of power in kW. These furnaces are also selected for tempering and high tempering.

The quality control of heat treatment is carried out by measuring the hardness of the part with devices TSH2 (Brinell press) or TK (Rockwell press).

Gearing Synthesis

For design, the number of wheel teeth z1 = 22, z2 = 32 and module m = 2 mm are given. Although z1 > zmin = 17, the gear must be cut with a tool offset to provide acceptable transmission performance.

From the blocking contour for the transmission, composed of gears with given numbers of teeth, we determine the displacement factors x1 = 0.55 ,

x2 = 1

3.2 Construction of involute engagement pattern

We draw a line of centers and, on a scale of 1.0 mm/mm, lay the axial distance aw = 56.67 mm. From the centers of rotation of the gear O1 and the wheel O2, we conduct circles: initial, main, dividing, vertices and recesses of the teeth.

We draw a common tangent to the main circles - the engagement line. It passes through the point of touch of the initial circles - the pole of engagement P, which indirectly indicates the correctness of the calculations.

On the main circles we build involvents. To do this, we lay a number of identical arcs and conduct tangents at the points of division. Along the tangents, we lay segments equal to the lengths of the bifurcation arcs. The resulting points lie on involvents. By depositing the normal tooth thicknesses along the dividing circles and displaying the involvents symmetrically, we build the full tooth profile. Perform wheel tooth templates.

We build a picture of a pair of teeth hooking in the pole, and then, laying the main step along the main circles, we build another pair of teeth.

Points of intersection of vertex circles with theoretical line of engagement give segment ab - working section of line of engagement.