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ME1001-BASIC MECHANICAL ENGINEERING
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ME1001-BASIC MECHANICAL ENGINEERING

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ME1001-BASIC MECHANICAL ENGINEERING. SYLLABUS. UNIT I– MACHINE ELEMENTS– I (5 hours) Springs : Helical and leaf springs – Springs in series and parallel. Cams : Types of cams and followers – Cam profile. UNIT II- MACHINE ELEMENTS– II (5 hours) - PowerPoint PPT Presentation
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Page 1: ME1001-BASIC MECHANICAL ENGINEERING

ME1001-BASIC MECHANICAL ENGINEERING

Page 2: ME1001-BASIC MECHANICAL ENGINEERING

SYLLABUSUNIT I– MACHINE ELEMENTS– I (5 hours) Springs: Helical and leaf springs – Springs in series and parallel. Cams: Types of cams and followers – Cam profile. UNIT II- MACHINE ELEMENTS– II (5 hours) Power Transmission: Gears (terminology, spur, helical and bevel gears, gear trains).

Belt drives (types). Chain drives. Simple Problems. UNIT III- ENERGY (10 hours) Sources: Renewable and non-renewable (various types, characteristics,

advantages/disadvantages). Power Generation: External and internal combustion engines – Hydro, thermal and

nuclear power plants (layouts, element/component description, advantages, disadvantages, applications). Simple Problems.

 

Page 3: ME1001-BASIC MECHANICAL ENGINEERING

SYLLABUSUNIT IV - MANUFACTURING PROCESSES - I(5 hours) Sheet Metal Work: Introduction – Equipments – Tools and accessories

– Various processes (applications, advantages / disadvantages). Welding: Types – Equipments – Tools and accessories – Techniques

employed -applications, advantages / disadvantages – Gas cutting – Brazing and soldering.

 UNIT V - MANUFACTURING PROCESSES– II (5 hours) Lathe Practice: Types - Description of main components – Cutting

tools – Work holding devices – Basic operations. Simple Problems. Drilling Practice: Introduction – Types – Description – Tools. Simple Problems.

Page 4: ME1001-BASIC MECHANICAL ENGINEERING

MACHINE ELEMENTS - I

CHAPTER -1

Page 5: ME1001-BASIC MECHANICAL ENGINEERING

SPRINGS

• A spring is an elastic body, which deflects under load and recover to its original shape upon release of the load.

• It is also resilient member which stores energy once deflected and releases the same as it recovers to its original shape.

Page 6: ME1001-BASIC MECHANICAL ENGINEERING

APPLICATIONS OF SPRINGS

1. Applying forces and controlling motions, as found in brakes and clutches.

2. Measuring force, as in the case of spring balance. Ex weighing machine (Analogue).

3. Storing energy, as in the case of clock springs & springs used in toys.

4. Reduce the effect of shock loading, as in the case of vehicle suspension ring.

5. Changing the vibration characteristics of machine mounted on foundation beds.

Page 7: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

1. Helical tension and compression spring:• The helical springs are made up of a wire coiled

in the form of a helix and are primarily intended for compressive or tensile loads.

• The cross-section of the wire from which the spring is made may be circular, square or rectangular.

• Helical compression springs have applications to resist applied compression forces

Page 8: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS• The major stresses produced in helical springs are

shear stresses due to twisting. The load applied is parallel to or along the axis of the spring.

Page 9: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

Helical compression spring

Page 10: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

2. Helical torsion springs:• The principal stress induced

are tensile and compressive due to bending.

• These are similar to the helical tension and compression springs.

• In these springs, the load is subjected to torsion about its axis.

Page 11: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

Helical torsion springs

Page 12: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

3. Spiral Springs: • The principal stress

induced are tensile and compressive due to bending.

• These are made of flat strip, wound in the form of spiral.

• This is subjected to torsion about its axis.

Page 13: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

Spiral Spring

Page 14: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

4. Leaf or laminated Springs :• The principal stresses are tensile and compressive de to

bending.• These are made of flat strips of varying lengths , clamped

together. • These may be cantilever, semi-elliptic or full elliptic in

form.

Page 15: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

Leaf Springs

Page 16: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

5. Belleville springs:• The principal stress are

tensile and compressive de to bending.

• These are made in the form of coned discs which may be stacked so as to give the required spring load-deflection characteristics.

Page 17: ME1001-BASIC MECHANICAL ENGINEERING

CLASSIFICATION OF SPRINGS

Belleville springs

Page 18: ME1001-BASIC MECHANICAL ENGINEERING

MATERIALS OF SPRINGS

• Commonly from alloy steels, High carbon steel (0.7 – 1 % C) or carbon alloy steel.

• The most common spring steels are music wire, oil tempered wire, silicon, Chrome vanadium.

• Stainless steel, Spring brass, Phosphor bronze, monel & titanium are used for corrosion resistance spring.

Page 19: ME1001-BASIC MECHANICAL ENGINEERING

TERMINOLOGY IN SPRINGS

Page 20: ME1001-BASIC MECHANICAL ENGINEERING

TERMINOLOGY IN SPRINGS• Solid Length :When the compression spring is compressed

until the coils come in contact with each other, then the spring is said to be solid. The solid length of a spring is the product of total number of coils and the diameter of the wire.

Solid length, L s = n x dWhere, n = number of coils

• Free Length (Lo) : The free length of a compression spring is the length of the spring in the free or unloaded condition.

Free length, Lo = Solid Length + Maximum Compression deflection + Clearance between adjacent coils (1mm).

Page 21: ME1001-BASIC MECHANICAL ENGINEERING

TERMINOLOGY IN SPRINGS• Spring Index (C): The ratio of mean coil diameter to wire

diameter. A low index indicates a tightly wound spring (a relatively large wire size wound around a relatively small diameter mandrel giving a high rate).

C=d/D• Spring rate(K): The Spring rate is defined as the force

required to produce unit deflection of the spring. It can also be said as stiffness or spring constant.

K =F/ ᵟ Where F is the load applied,

ᵟ is the deflection of the spring.

Page 22: ME1001-BASIC MECHANICAL ENGINEERING

TERMINOLOGY IN SPRINGS

• Pitch (P) : The distance from center to center of the wire in adjacent active coils. The pitch of the coil is defined as the axial distance between adjacent coils in uncompressed state.

P = Free length / (n-1)

Page 23: ME1001-BASIC MECHANICAL ENGINEERING

SPRING COMBINATIONS

• Parallel arrangement: In parallel the spring are arranged side by side. The deflection in spring combination is equal to individual spring.

Ke = K1 + K2 + ...... + Kn

Page 24: ME1001-BASIC MECHANICAL ENGINEERING

SPRING COMBINATIONS

• Series Arrangement: When the spring are arranged in series, the total deflection of the spring combination is equal to sum of the deflection of individual springs.

1/ Ke = 1/ K1 + 1/ K2 +... + 1/ Kn

Page 25: ME1001-BASIC MECHANICAL ENGINEERING

CAM

• CAM is a device used to convert one simple motion such as rotation to any other motion.

• A CAM mechanism consist of two moving elements, the cam and the follower which is mounted on the frame.