IV. RESULTADOS Y DISCUSIONES
4.5 Proponer un proceso de mejora de la calidad en el proceso de
4.5.2 Propuesta de mejora
REPORT
JJ615 MECHANICALCOMPONENTS & MAINTENANCE (GEAR DRIVES)
CLO:
1. Assemble correctly mechanical component base on service manual maintenancebygroup.(P5)
2. Organize properly maintenance procedure base on standard operation procedure.(A4)
1.
NAME:
REGISTERATIONNO: SESSION:
PROGRAMME
PRACTICAL DATE SUBMITTED DATE
TITLE : ASSEMBLE AND DISASEMBLE OF GEAR DRIVE SYSTEM
1.0 COURSE LEARNING OUTCOMES
Upon completion of this workshop, students should be able to :
1.1 Assemblecorrectlymechanicalcomponent base onservicemanualmaintenance by group. (P4) 1.2 Organizeproperlymaintenanceprocedurebaseonstandardoperation procedure.
(A4)
1.3 Practice safety procedures correctly in the working workshop according to the workshop safety regulation to create a secure practical team work (A3).
2.0 OBJECTIVES
2.1 Producemaintenanceprocedure for a gear drives drives.
2.2 Assembleanddisassembleagear drives system as a practical.As an examplescomponentcanbe
use is gear station unit.
3.0 APPARATUS/EQUIPMENT
It is the individual’s responsibility to practice the following general safety guidelines at all times and keep your workspace reasonably tidy.
4.1 Always know the hazards associated with the equipment/materials that are being utilized in the workshop.
4.2 Always wear appropriate protective clothing and equipment.
4.3 Confine long hair and loose clothing. Do not wear high-heeled shoes, open-toed shoes, sandals
or shoes made of woven material.
4.4 Be familiar with the location of emergency equipment such as fire alarm and fire extinguisher.
Know the appropriate emergency response procedures.
5.0 INTRODUCTION
A gear is a rotatingmachine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, magnitude, and direction of a power source. The most common situation is for a gear to mesh with another gear, however a gear can also mesh a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.
The gears in a transmission are analogous to the wheels in a pulley. An advantage of gears is that the teeth of a gear prevent slipping.
When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship.
In transmissions which offer multiple gear ratios, such as bicycles and cars, the term gear, as in first gear, refers to a gear ratio rather than an actual physical gear. The term is used to describe similar devices even when gear ratio is continuous rather than discrete.
6.0 TOOLS:
NO TOOLS DESCRIPTION TOOLS USAGE
7.0 DIASSEMBLE AND ASSEMBLE PROCEDURES:
NO EXPLANATION FIGURES/SKETCHES 1
2
3
4
.
ETC
8.0 COMPLETE MAINTENANCE PROCEDURE FOR A GEAR DRIVES
9.0 DISCUSION / CONCLUSION
1. PRACTICLE RUBRIC
RUBRIC FOR COMBINE GEAR DRIVE SYSTEM PRACTICLE
Generic Student Attributes
(GSA) / Learning
Domain (LD)
Skills /
Aspects Excellent Very
Good Good Fair Unsatisfactory
5 4 3 2 1
LD 2 /
3.2.7Developmaintenanceprocedure for a gear drive system.
Belt Drives in Power Transmission
A belt is a looped strip of flexible material, used to mechanically link two or more rotating shafts.
They may be used as a source of motion, to efficiently transmit power, or to track relative movement. Belts are looped over pulleys.
In a two pulley system, the belt can either drive the pulleys in the same direction, or the belt may be crossed, so that the direction of the shafts is opposite.
Figure 3.1: Belt Drive 3.3.1 List of Belt Drives Applications
Transmit Power
A combination of mechanical components to change the speed or torque of mechanical energy. Transmit power is achieved by specially designed belts and pulleys. One or both of the pulleys are powered to moving the belt. The powered pulley is called the drive pulley while the unpowered pulley is called the idler.
Figure 3.2: Power transmission using belt drive
Conveyor.
A conveyor system is mechanical handling equipment that moves materials from one location to another. Conveyors are especially useful in applications involving the transportation of heavy or bulky materials
Figure 3.3: Conveyor
Industries using these applications are:
• Automotive
• Blenders
• Converting
• Conveyors
• Farming
• Feeder Drives
• Food Processing
• Electrical generators
• Robotics
• Medical
• Mixers
• Movie Animation
• Office Machines
• Packaging
• Electrical generators
• Power Transmission Distributors
• Material Handling
3.3.2 5 Types Of Belt Drives
Table 3.1: Types of Belt Drives
1. Flat belts - used to transfer power from the engine's flywheel. It can deliver high power at high speeds (500 hp at 10,000 ft/min), in cases of wide belts and large pulleys. It can deliver high power at high speeds (500 hp at 10,000 ft/min), in cases of wide belts and large pulleys. Flat belts were traditionally made of leather or fabric. Today some are made of rubber or polymers.
2. Round belts - Round belts are a circular cross section belt designed to run in a pulley with a 60 degree V-groove. Round grooves are only suitable for idler pulleys that guide the belt, or when (soft) O-ring type belts are used. The V-groove transmits torque through a wedging action, thus increasing friction.
Nevertheless, round belts are for use in relatively low torque situations only and may be purchased in various lengths or cut to length and joined, either by a staple, a metallic connector (in the case of hollow plastic), gluing or welding (in the case of polyurethane). Early sewing machines utilized a leather belt, joined either by a metal staple or glued, to great effect.
3. Vee belts - (also known as V-belt or wedge rope) solved the slippage and alignment problem. It is now the basic belt for power transmission. They provide the best combination of traction, speed of movement, load of the bearings, and long service life. They are generally endless, and their general cross-section shape is trapezoidal (hence the name "V"). The "V"
shape of the belt tracks in a mating groove in the pulley (or sheave), with the result that the belt cannot slip off. Optimal speed range is 1000–7000 ft/min.
4. Multi-groove belts or polygroove belt - is made up of usually 5 or 6 "V" shapes alongside each other. This gives a thinner belt for the same drive surface, thus it is more flexible, although often wider. The added flexibility offers an improved efficiency, as less energy is wasted in the internal friction of continually
bending the belt. In practice this gain of efficiency causes a reduced heating effect on the belt and a cooler-running belt lasts longer in service. They can run over pulleys on the ungrooved back of the belt.
5. Ribbed belt - is a power transmission belt featuring lengthwise grooves. It operates from contact between the ribs of the belt and the grooves in the pulley. Its single-piece structure is reported to offer an even distribution of tension across the width of the pulley where the belt is in contact, a power range up to 600 kW, a high speed ratio, serpentine drives
(possibility to drive off the back of the belt), long life, stability and homogeneity of the drive tension, and reduced vibration. The ribbed belt may be fitted on various applications: compressors, fitness bikes, agricultural machinery, food mixers, washing machines, lawn mowers, etc.
6. Film belts - though often grouped with flat belts, they are actually a different kind. They consist of a very thin belt (0.5-15 millimetres or 100-4000
micrometres) strip of plastic and occasionally rubber.
They are generally intended for low-power (10 hp or 7 kW), high-speed uses, allowing high efficiency (up to 98%) and long life. These are seen in business machines, printers, tape recorders, and other light-duty operations.
7. Toothed belts (also known as timing, notch, cog, or synchronous belts) - are positive transfer belts and can track relative movement. These belts have teeth that fit into a matching toothed pulley. When correctly tensioned, they have no slippage, run at constant speed, and are often used to transfer direct motion for indexing or timing purposes. They can bear up to 200 hp (150 kW) at speeds of 16,000 ft/min.
* choose 5 types only
3.3.3 Belt tension and misalignment of belt drives
Belt tension
• The ideal belt is that of the lowest tension which does not slip in high loads.
• Belt tensions should also be adjusted to belt type, size, speed, and pulley diameters.
• Belt tension is determined by measuring the force to deflect the belt a given distance per inch of pulley.
• Timing belts need only adequate tension to keep the belt in contact with the pulley.
Figure: 3.4: belt tensioner Misalignment
Belt drive misalignment exists when the driver and driven sheaves are not properly aligned.
Misalignment can take either the form of angular or parallel (offset) misalignment, or a combination of both.
Angular misalignment occurs when the faces of the sheaves do not form a straight line.
With parallel misalignment, the sheaves may be in angular alignment, but their position on the shaft creates a parallel offset.
Angular misalignment. Parallel misalignment.
Figure 3.5: misalignment
3.3.4 Check list drive belt maintenance
There are several things need to be addressed before performing maintenance is charged which is:
Always shut off power, lock and tag control box.
Place all machine components in safe position.
Remove guard, inspect and clean.
Inspect belt for wear, damage. Replace as needed.
Inspect sheaves or sprockets for wear, alignment. Replace if worn.
Inspect other drive components such as bearings, shafts, motor mounts and take up rails.
Inspect static conductive grounding system (if used) and replace components as needed.
Check belt tension and adjust as needed.
Recheck pulley alignment.
Reinstall belt guard.
Restart drive. Look and listen for anything unusual.
Table 3.2: Table of symptoms, probable cause and solution