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Drive of inductance adjustment mechanism - drawings, design part

  • Added: 09.07.2014
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The drive of the inductance adjustment mechanism is a course project on applied mechanics, there is a DBE

Project's Content

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Additional information



1 Setting of the task

2 Electric motor selection

3 Rack gear calculation

3.1 Definition of allowable stresses

3.2 Determination of geometric parameters of transmission

3.3 Rack parameters

3.4 Forces in engagement

3.5 Comparative characteristics of teeth bending strength

3.6 Check of teeth bending strength

4 Determination of motor speed

5 Calculation of cylindrical gears

5.1 Material Selection

5.2 Design factors

5.3 Calculation of service life of the mechanism

5.4 Calculation of moments

6 Calculation of the second cylindrical spur gear

6.1 Definition of allowable stresses

6.2 Determination of geometric parameters of transmission

6.3 Checking the contact strength of teeth

6.4 Forces in Engagement

6.5 Comparative characteristic of bending strength of teeth

6.6 Check of teeth bending strength

7 Calculation of the first cylindrical spur gear

7.1 Definition of allowable stresses

7.2 Determination of geometric parameters of transmission

7.3 Checking the contact strength of teeth

7.4 Forces in engagement

7.5 Comparative Characteristics of Bending Strength of Teeth

7.6 Check of teeth bending strength

8 Calculation of interference landings

8.1 Calculation of landing of gear wheel 1

8.2 Calculation of gear 2 landing

8.3 Calculation of landing of gear wheel 2

8.4 Selection of gear fit on motor shaft

9 Shaft calculation

9.1 Design Calculation

9.2 Verification calculation

9.3 Static Strength Calculation

9.4 Fatigue resistance calculation

10 Shaft and axle supports

10.1 Calculation of rolling bearings

11 Housings and Housing Parts


List of sources used


Scientific and technological progress is impossible without the creation of accurate actuators of instrument devices. In general, the drive consists of a power source, a gearbox and control equipment. The energy source is the motors: thermal, electrical, pneumatic, spring, etc.

Reduction gear can consist of friction, gear, hinge-spring, cam and other gears. Preferably, this is a multistage downshift. Some instruments, such as clock mechanisms, reporting devices, use booster gears - multipliers.

According to the purpose, mechanical transmissions are divided into reporting (kinematic), high-speed and power. The main requirements for reporting gears are high accuracy of converting the angle of rotation from the driving shaft to the driven shaft, to high-speed gears - smoothness of operation, to power gears - good fit of teeth on side surfaces in order to reduce contact pressures and increase their wear resistance.

5 calculation of cylindrical gears

5.1 Material Selection

Materials of gears are selected depending on purpose and conditions of transmission operation. Carbon or alloyed steels are used, less often plastics and non-ferrous metals. Heat treated steels are the main material for gears. Heat treatment is carried out to increase hardness.

For better tapping of teeth and their uniform wear for spur gears, it is recommended that the hardness of the working surfaces of the gear teeth be assigned more hardness of the wheel teeth by 20 30 HB units, i.e. HB1 = HB2 + 20 30. This recommendation is caused by the fact that the gear for one turn of the wheel engages with it a gear ratio of times more, and therefore the possibility of fatigue destruction of it is higher.

Choose steel 45 as the material (thermal treatment - improvement, limit of contact endurance but, = 2HV + 70 = 641n/mm2, limit of tooth endurance at bending FO = 1.8HB = 514 n/mm2), and steel 35 wheels (thermal treatment - normalization, limit of contact endurance but, = 2HV + 70, mm2 = 5m2 combinations of such stems

5.2 Design factors

Coefficient of wheel rim width relative to axial distance, where b2 is wheel rim width, mm; aw is the axial distance, mm. The width factor a is taken from a number of standard numbers depending on the position of the wheels relative to the supports. In our case, the symmetrical arrangement of the wheels, so.

The non-uniformity factors of the load distribution over the width of the gear ring when calculating the contact strength of the CP and when calculating the bending KF depend on elastic deformations of the shafts, housings, the gears themselves, errors in manufacturing and assembly, wear of the bearings that cause the teeth of the mating wheels to be pumped relative to each other.

In running-in gears in which the material of both wheels or at least one of the wheels has a hardness of 350 LV, and the circumferential speed of the wheels is 15 m/s, the unevenness of the load across the width of the rim gradually decreases and can be completely eliminated due to local wear, that is, tapping of the teeth occurs. Therefore, for running-in wheels of cylindrical and spur conical at hardness of at least one of wheels less than 350 LV and speed of 15 m/s, KH = KF = 1 is accepted.

Dynamic load factors KN and KF take into account the occurrence of additional dynamic loads in the wheel engagement. The values of these coefficients depending on the hardness of the wheel are given in the table. In our case KN = 1.2 KF = 1.4.

The factors KN and KF take into account the uneven distribution of load between the teeth. For spur wheels KN = KF = 1.


Modern devices often use mechanical mechanisms, for example, rack gear is used in disk drives. In this course project, I calculated the mechanism of inductance restructuring used in radio electronics. The skills gained in calculating this project will help me become a good engineer.

Drawings content

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