Theory of Mechanisms and Machines - Design of the Lever Mechanism

Contents

Introduction

Job for coursework

1 Structural analysis of the mechanism

2 Kinematic analysis of mechanism

2.1 Determination of speeds of mechanism link points

2.2 Determination of angular velocities of mechanism links

2.3 Determination of accelerations of mechanism link points

2.4 Determination of angular accelerations of mechanism links

3 Gear Design

3.1 Calculation of geometrical parameters of gear engagement

3.2 Calculation of gear diameters

3.3 Calculation of dimensions for gears inspection

3.4 Calculation of common normal length

3.5 Construction of involute engagement pattern

3.6 Gear Quality Indicators and Dimensions Required for Gear Control

Conclusions

List of sources used

Introduction

The theory of Machines and Mechanisms, the science of general methods for the study and design of machines and mechanisms. The most developed part of science is called mechanism theory, which studies mainly the properties of mechanisms that are common to all (or for certain groups) of mechanisms, regardless of the specific purpose of the machine, device or apparatus .

For example, the same mechanism for converting rotational motion, made in the form of gear wheels, can be used in cars, watches, stirrers of chemical devices. In all these cases, the same motion transformation is required, so the methods of research and design of these mechanisms have much in common and constitute the content of the theory of mechanisms. Another part of science is machine theory, which examines research and design methods that are common to machines in various fields of technology. Both parts of science are inextricably linked, since mechanisms form the basis of almost any machine.

The design, manufacture and correct operation of mechanisms involves knowledge of the physical processes underlying the operation of devices, the methods of calculation used, the principle of designing units and parts.

Each mechanism consists of a large number of parts, connected to each other in a certain way. The duration of their operation depends on the structural shape, accuracy of manufacture, material and other factors. When creating any mechanisms, attention should be paid to issues of technicality and economy.

Job for coursework

Dimensions of lever mechanism links

lOA=0,11 m

lAB=0,48 m

lCB=lBD=0,28 м

a = 0.27 m

b = 0.50 m

Crankshaft speed

n1 = 80 rpm

Crank position at power calculation

1=30°

Number of gear wheel teeth

z1=14

z2=23

Transmission wheel module

m=7

Conclusions

The purpose of the calculation and graphic work is to consolidate the theoretical knowledge that was obtained during the study of the TMM course, familiarization with the methods of designing mechanisms. The first stage of designing any mechanism is the compilation of its kinematic scheme, the calculation of kinematic parameters, the determination of the load of various parts and the energy characteristics of the mechanism as a whole.

Performing calculation and graphic work on TMM, he mastered the methods for determining the kinematic parameters of mechanisms, assessing the forces that act on individual links of the mechanism, learned to creatively evaluate the designed mechanism from the point of view of its purpose - to provide the necessary parameters for the movement of the link.

Involute gear engagement was calculated. Gear and wheel tooth profile drawing is made.