MAZ-509 rear axle reduction gear box

Contents

TABLE OF CONTENTS

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1. Purpose of main transmission of MAZ-509 vehicle and requirements for it

2. Kinematic diagram of the designed unit

3. Material selection for main parts

4. Determination of geometrical shape and dimensions of basic parts

5. Calculation for contact fatigue

6. Calculation of teeth for bending fatigue

7. Calculation of gears for strength

8. Calculation of main gear shafts for static strength

9. Selection of bearings

10. Comparison of the design of the developed unit

with a similar prototype node

List of literature

Purpose and requirements of the main transmission of the vehicle MAZ509

The main gear is designed to increase torque and reduce the speed of rotation of the driving wheels to the required values, as well as to transfer rotational motion at an angle.

The main transmission shall meet the following requirements:

- ensure high traction and dynamic qualities and fuel

cost-effectiveness;

- have a high efficiency;

- ensure low level of vibration and noise;

- have minimum height dimensions from centerline: down - for

meeting ground clearance; up to lower the floor level;

- have sufficient strength and rigidity at minimum weight.

The main gears according to the number, type and location of the gears are divided into single, double, conical, hypoid, cylindrical, worm, central, double, spaced double, two-stage.

Single conical main gear is used on light-duty cars and trucks.

A single hypoedic main transmission has become more widespread, with a number of advantages: increased carrying capacity in contact voltages, smooth operation and quiet.

Single cylindrical main gear is widely used on passenger cars, especially front-wheel drive ones, in the transverse arrangement of the engine.

Single worm gear allows you to obtain a gear ratio of more than 7. However, the low efficiency of the worm gear compared to the conical and hypoid gear, the reduced carrying capacity at the same dimensions and the slightly increased production cost limit the scope of such gears.

Double spaced main gear consists of central reduction gear with single conical gear and inter-wheel differential, behind which two reduction gears are located in drive of each driving wheel.

The dual central main gear has a large size, weight and cost compared to a single gear, but allows to obtain a large gear ratio without reducing the ground clearance under the main gear crankcase.

Material Selection for Main Parts

The drive bevel gear is made of 20XGNMTA material, cemented to a depth of 1.2... 1.5 mm to the hardness of the surface of the teeth HRC 57... 64, and the core of the teeth HRC 32... 45.

The driven bevel gear is made of 15XGN2TA material, cemented to a depth of 1.2... 1.5 mm to the hardness of the surface of the teeth HRC 57... 64, and the core of the teeth HRC 32... 45; it has also been phosphated to improve the run-in.

Characteristics of material according to GOST:

20HGNMTA:

20% carbon, 1.5% chromium, 1.5% manganese, 1.5% nickel ,

1.5% molybdenum, 1.5% titanium, A - high-quality steel.

15HGN2TA:

15% carbon, 1.5% chromium, 1.5% manganese, 1.5% nickel ,

2.0% titanium, A - high-quality steel.

Compare the design of a developed node with a similar prototype node

The designed unit (main gear) was developed on the basis of a similar unit of the MAZ509 prototype car, therefore, significant differences in design were not made, the main difference is the change in the geometric dimensions of the parts of the designed unit, this is due to a change in the maximum torque output by the engine, an increase in the maximum speed of the engine crankshaft, a decrease in the weight of the car and its carrying capacity.

List of literature used

1. Lukin P.P., Gasparyants G.A. Design and calculation of automobiles. -M: Mechanical Engineering, 1984.376 p.

2.Mobiles: Design, Design and Calculation. Transmission, A.I. Grishkevich, A.V. Karpov and others; Ed. A.I. Grishkevich. - M.: Vys. sq., 1985.240 s.

3. Zhigalov A.M. Car theory: Methodological guidelines for course work. -Archangelsk: Publishing House ALTI, 1979.36s.

4. Myasishchev D.G. Forest vehicles: Methodological guidelines for the performance of course work. - Arkhangelsk: RIO AGTU, 1994. – 32 pages.

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