Design and study of dynamic loading of wheel tractor machine unit

Contents

Contents

1. Introduction

2 Description of machine operation and initial design data

3. Investigation of machine unit dynamic loading

4. Dynamic synthesis and analysis of machine unit

4.1. Setting the task of dynamic synthesis and analysis of machine unit

4.2. Structural analysis of lever mechanism links

4.3. Determination of dimensions of links of lever mechanism, masses, position of center of mass, moments of inertia of links of lever mechanism

4.4. Calculation of kinematic characteristics of lever mechanism

4.4.1. Drawing up plans for the provisions of the mechanism

4.4.2. Plan speed analogues

4.4.3. Calculation of 1 transfer function

4.4.4 Drawing up of algorithm diagram for determination of kinematic characteristics of lever mechanism

4.4.5 Calculation of kinematic characteristics of lever mechanism in control position i =

4.5 Construction of indicator diagram and calculation of gas pressure on piston

4.6 Dynamic model selection and justification

4.7 Diagram of algorithm for determination of reduced moment of driving forces and calculation in one control position

4.8 Algorithm for determination of reduced moment of inertia

4.9. Calculation in reference position of variable component of reduced moment of inertia

4.10 Compilation of algorithm diagram in determination of angular velocity and angular acceleration of dynamic model drive link

4.11 Preparation of initial data for computers and calculation of computers

4.12 Plot kinematic characteristics

4.12.1 Plotting of dependence SB = SBsound

4.12.2 Plotting of dependence i31 = i31sound

4.12.3 Plotting of dependence i31 = i31sound

4.13 Graph of variable component of reduced moment of inertia

4.13.1 Creation of the schedule of the making A=Aφ

4.13.2 Creation of the schedule of the making B=Bφ

4.13.3 Creation of the schedule of the making C=Cφ

4.13.4 Graph of the variable component of the reduced moment of inertia IPII = IPIIa

4.14 Construction of graphs of given moments of forces

4.14.1 Graph of the reduced moment of motive forces MPD = MPD

4.14.2 Graph of reduced moment of resistance forces of MPS = MPS

4.15 Construction of force operation schedules

4.15.1 Creation of the schedule of work of driving forces HELL =ADφ

4.15.2 Creation of the schedule of works of forces of resistance of AC=ACφ

4.16 Plot the change of the kinetic energy of the machine and the change of the kinetic energy of the constant component of the reduced moment of inertia

4.16.1 Graph of change of kinetic energy of machine ∆T=∆T (¼ 1)

4.16.2 Graph of change of kinetic energy of constant component of reduced moment of inertia ∆TI=∆TI (¼ 1)

4.16.3Determination of DC component of reduced moment of inertia

4.17 Plotting of angular velocity change ∆ω1=∆ω1 (¼ 1)

4.18 Construction of angular acceleration graphs α1 = α1 (¼ 1) of the drive link

4.19 Determining the dimensions and parameters of the flywheel

4.20 Conclusions on section

5. Dynamic Lever Analysis

5.1 Tasks of dynamic analysis of lever mechanism

5.2 Kinematic analysis of lever mechanism

A. Graphical solution of the problem

5.2.1 Construction of the mechanism position plan in the control position

5.2.2 Constructing the speed plan of the mechanism and calculating the speeds of all points and links of the mechanism

5.2.3 Construction of the acceleration plan of the mechanism

B Analytical solution of the problem

5.2.4 Calculation of acceleration speeds of all points and links of the mechanism

5.3 Determination of forces acting on the mechanism links:

5.4 Power calculation of lever mechanism

A) Graphical solution method

5.4.1 Power calculation of Assur group (2-3)

5.4.2 Plan of forces of Assur group (2-3)

5.4.3 Determination of reaction parameters in kinematic pairs of Assur group (2-3)

5.4.4 Construction of class I mechanism forces diagram

5.4.5 Determination of balancing moment

5.4.6 Construction of the force plan of the input link

B) Analytical method of solution

5.5 Drawing up diagram of power calculation algorithm of Assur group 2-3 and I class mechanism

5.6 Calculation of reaction parameters and balancing moment in the control position

5.7 Comparative analysis of force calculation

5.8 Preparation of initial data for computers and calculation on computers

5.9 Creation of a godograf of reaction in rotary couple of O R10 (φR10)

5.10. Creation of a godograf of reaction in rotary couple And R21 (φR21)

5.11. Construction of reaction hodograph in rotary pair B R23 (¼ R23)

5.12 Plot the reaction in translational pair B R30 (SB)

5.13 Analysis of constructed hodographs and graphics

5.14 Conclusions under

6 Synthesis of cam mechanism

6.1 Setting the task of dynamic synthesis of cam mechanism

6.2 Selection of initial data for cam mechanism design

6.3 Kinematic analysis of pusher motion

6.3.1 Diagram of algorithm for determination of kinematic characteristics of pusher

6.3.2. Calculation of kinematic characteristics of the pusher in two reference positions

6.3.3. Calculation of extreme speed values and their corresponding pusher movements

6.4. Create a simplified blend chart and define the basic dimensions of the mechanism

6.5. Diagram of algorithm for determination of polar coordinates of cam center profile

6.6. Calculation of polar coordinates in two control positions

6.7 Computer Design and Computer Calculation

6.8 Construction of kinematic diagrams of pusher motion

A) Diagram of pusher movement from phase angle (STi (¼ i))

B) Diagram of pusher speed analogue from phase angle (S'Ti (¼ i))

C) Diagram of pusher acceleration analogue from phase angle (S "" Ti (¼ i))

6.9 Construction of a complete combined diagram (ST-S 'T) and determination of refined values of the main dimensions of the mechanism

6.10 Construction of cam center profile by reverse motion method

6.11 Determination of roller radius and construction of actual cam profile

6.12 Plotting of pressure angle and check for absence of pusher jamming (Ɵ (¼ i))

6.13. Conclusions to Section

Conclusion

List of literature

Application

Description of the electronic CD-ROM

Description of the electronic CD-ROM

Attached in the explanatory note is a CDR CD that records the electronic files of the course project.

When you open the CD, we will see a folder, course design, which contains 6 files made in the Microsoft Word 2010 package and 3 files made in the COMPAS3DV13 package.

Dynamic synthesis and analysis of machine unit

4.1. Setting the task of dynamic synthesis and analysis of machine unit

Machine unit dynamics tasks:

Dynamic synthesis of machine unit with lever mechanism by preset coefficient of non-uniformity δ and determination of constant part of moment of inertia and moment of inertia of flywheel.

Dynamic analysis of the motion of the link with the determination of the actual angular velocity [omega] and angular acceleration [omega] within the steady-state motion cycle. The main most energy intensive is the internal combustion engine.

Dynamic Lever Analysis

5.1. Setting the task of dynamic analysis of lever mechanism

The tasks of dynamic mechanism analysis are:

1) determination of reactions in kinematic pairs;

2) determination of balancing moment (resistance) acting on the crank shaft on the drive side.

At the same time the law of the movement of a crank ω1 (φ1) and ε1 is known (φ1).

These problems are solved by the kinetostatics method based on the D'Alembert principle. This method involves the introduction of inertial loads (main vectors and main moments of inertia forces), to determine which you need to know the accelerations of the centers of mass and the angular accelerations of the links. Therefore, the force calculation is preceded by a kinematic analysis of the mechanism according to the already known crank rotation law (1, 1).

5.13. Analysis of constructed hodographs, graphics and balancing moment

When performing calculations, all reaction vectors in kinematic pairs were determined, and a balancing moment was also determined.

We analyze the reactions R10, R21, R23 .

The reactions R10, R21 do not spread over the entire surface of the rotational pairs O, A, but at angles of 63 ° and 60 ° have the greatest value at position 1.

The reaction R23 extends to a small angle of 22 ° and has the highest value at position 1. Section 1-4 will be the most loaded, since the reactions in this section have maximum values. When moving from position 12 to position 1, an impact will be observed, since the reactions drastically change direction.

The hole for oil supply to the connecting rod bearing should be made at the place of lowest pressure on the connecting rod journal.

Consider the dependency graph R30 (SB). When the piston moves from TMM to NMT, it is pressed to one of the cylinder walls. The reaction will be most important at position 2. When the piston moves from the MMT to the MMT, the piston presses to the other side of the cylinder. The reaction in this case has a maximum value at position 11. Based on this, it can be concluded that one of the cylinder parts will be subjected to greater loads than the other, therefore, as it wears, the cylinder will take an elliptical shape .

5.12 Conclusions under

During the section, calculations were made by graphical and analytical methods of the values ​ ​ of all forces and reactions acting on the crank-slide mechanism. Hodographs of reactions in all kinematic pairs were built, and their analysis was also made.

From the analysis of the performed study it follows:

1. Reactions R10, R21 have maximum values at position 1.

2. Reaction R23 has a maximum value at position 1.

3. During the entire steady-state cycle, the equilibrium moment has a constant MU = 380.3 Nm, which coincides with the value of the reduced moment of the TIR driving forces obtained during the study of the machine dynamics (Section 4).

Conclusion

In section 4 "Dynamic synthesis and analysis of the machine unit," graphical and analytical calculations of the main kinematic characteristics of the machine unit were made: lOA = 0 06 m, lAB = 0 .3 m, lAS2 = 0 09 m, m1 = 19.2 kg, m2 = 2.4 kg, m3 = 2.9 kg, IS2 = 0.032 kg/m2. Since the reduced moment of inertia of all rotating links IP0 < IPI, it is necessary to install a flywheel on the crank shaft, the moment of inertia of which is IM = 5.116 kg∙m2, which is provided in the form of a steel disk with a diameter of dm = 0.505 m and a mass of mm = 79.36 kg. Graphs of kinematic characteristics dependencies on the crank angle, as well as dependencies of the variable component of the reduced moment of inertia, power characteristics, kinetic energy on the angle of rotation of the crank were built.

In section 5 "Dynamic analysis of the lever mechanism," kinematic characteristics were also calculated by graphical and analytical methods. By the method of kinetostatics, all forces acting on the mechanism, including inertial loads, as well as reactions in the kinematic pairs of the mechanism, were determined and hodographs of these reactions from the angle of the crank were built. This section provides a detailed analysis of these hodographs. A balancing moment was determined that turned out to be Mu=380,3N∙m.

In section 6 "Dynamic synthesis of the cam mechanism," the kinematic characteristics of the pusher were calculated, the laws of motion of the pusher were chosen, based on which the main dimensions of the cam mechanism were determined: r0 = 0.0278 m, los = 0,1573 m, rp = 0,0112 m. A combined diagram and cam profile were built that ensures the movement of the pusher according to the given law of motion .