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Gear System
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SUBJECT : ENGINEERING LABORATORY IV (BDA 2721)CODE
: BDA 2711
TOPIC
: COMPUTERIZED GEAR SYSTEM
OBJECTIVES :i. Describe the different type of gear system and some of their applicationii. Calculate gear ratios, angular velocity, input and output torque.iii. Calculate the efficiency of the gears.LEARNING OUTCOMES :i. Understand the concept of gear system, types of gears and its related function and
application.ii. Implement and analyze the required data collectively within member of group.iii. Produce good technical report according to the required standard
THEORY :Gears are used to transmit motion, and therefore power, between one shaft and another shaft. The function of a gear box is to transmit rotational motion from a driving prime mover to a driven machine. Gear also knows as a toothed wheel designed to transmit torque to another gear or toothed component. Different size gears are often used in pairs, allowing the torque of the driving gear to produce a large torque in the driven gear at lower speed, or a smaller torque at higher speed. The large gear known as wheel and the smaller gears as a pinion. Consider a simple schematic of a gear box with an input and output shaft as shown in Figure 1.
Figure 1
And another theory of gear is a component within a transmission device that transmits rotational torque by applying a force to the teeth of another gear or device. A gear is different from a pulley in that a gear is a round wheel that has linkages ("teeth" or "cogs") that mesh with other gear teeth, allowing force to be fully transferred without slippage. Depending on their construction and arrangement, geared devices can transmit forces at different speeds, torques, or in a different direction, from the power source.
The gear's most important feature is that gears of unequal sizes (diameters) can be combined to produce a mechanical advantage, so that the rotational speed and torque of the second gear are different from those of the first. In the context of a particular machine, the term "gear" also refers to one particular arrangement of gears among other arrangements (such as "first gear"). Such arrangements are often given as a ratio, using the number of teeth or gear diameter as units.
Gear Types
internal gears
Worms Gear
Spur gears
Bevel gears
Gear ratio, G.R = Input Speed / Output Speed, = N1 / N2Gear ratio, G.R = (product of driven teeth)/(product of driving teeth)Gear ratio, G.R = Input Speed / Output Speed,
= 1 / 2The power transmitted by a torque,T (Nm) applied to the shaft rotating at N (rev/min) is given by :-
Power,
P = T
P = [ 2NT] / 60In the ideal gearbox, the input and output power are the same so,
[2N2T2] / 60 = [2N1T1] / 60In a real gear box, power is lost through friction and the power output is smaller than the power input.The efficiency is defined as;
= Power Output / Power Input
= [2N2T2 x 60] / [2N1T1 x 60]
= T11 / T11Note:-
N speed in rev/min
angular velocity (rad/s)Table 1 : Technical Specification for Equipment
Type of GearClass of GearDescriptionGear
1234
4 - StageSame Sizea. No of teeth18787878
b. Pitch diameter36156156156
c. Outside diameter40160160160
4 - StageDifferent Sizea. No of teeth183878118
b. Pitch diameter3676156232
c. Outside diameter4080160236
EQUIPMENT :ITEMNO
Unit of Gear Set2
Control Panel1
Computer Set1
Printer1
Protective Transparent Cover1
Equipment
Figure 3 : Overall SystemPROCEDURES :A. EXPERIMENT FOR 4 STAGE GEAR WITH SAME SIZE GEAR - GEAR SET 11) Make sure gear set 1 is in place. If not, install the gear set 1 into the system according to the following steps:- i. Remove the transparent protective cover of the system.
ii. Disconnect the sensor cable. Remove the locking bolts of the gear set.
iii. Remove the gear set by lifting it using the handles.
iv. Put the removed gear set lifting on storage table.
v. Take the new gear set and put it on system. Make sure the gear set is completely in place.
vi. Tighten the locking bolts. Connect the sensor cable.
vii. Put the transparent protective cover of the system. The new set is ready to operate.
2) Turn on the computer. Turn on the Infix gear software.
3) Turn on the system by pressing ON button. The controller and motor displays will ON.
4) Slowly increase the speed until it reaches 100rpm. Record the motor speed into the lab sheet accordingly.
5) Press RECORD on the monitoring page software. Let the system run and stabilize for an about 10 seconds.
6) Slowly increase the speed until it reaches 200rpm. Record the motor speed into the lab sheet 1.
7) Let the system run and stabilize for about 10 seconds.
8) Follow the step 5.1.6 to 5.1.7 for the speed adjustment of 300rpm, 400rpm, 500rpm, 600rpm, and 700rpm.
9) Turn OFF the potentiometer slowly.10) Record all values into your lab sheet.B. EXPERIMENT FOR 4 STAGE GEAR WITH DIFFERENT SIZE GEAR GEAR SET 2
1) 5.2.1.Make sure gear set 2 is in place. If not, install the gear set 2 into the system according to the steps 5.1.1. (i vii).
2) 5.2.2.Turn on the computer. Turn on the Infix gear software.
3) 5.2.3.Turn on the system by pressing ON button. The controller and motor displays will ON.
4) 5.2.4.Slowly increase the speed until it reaches 100rpm. Record the motor speed into the lab sheet accordingly.
5) 5.2.5.Press RECORD on the monitoring page software. Let the system run and stabilize for an about 10 seconds.
6) 5.2.6.Slowly increase the speed until it reaches 200rpm. Record the motor speed into the lab sheet 1 accordingly.
7) 5.2.7.Let the system run stabilize for about 10 seconds.
8) 5.2.8.Follow the step 5.1.6 to 5.1.7 for the speed adjustment of 300rpm, 400rpm, 500rpm, 600rpm, and 700rpm.
9) 5.2.9.Turn OFF the potentiometer slowly.
10) 5.2.10.Record all values into your lab sheet.
OBSERVATIONS :
TABLE 2 : 4 Stage Gear with Same Size Gear Gear SetGear 0
( Motor )
Gear 1
Gear 2
Gear 3
No of teeth (t)18787878
Pitch Diameter (D) mm36156156156
Gear Ratio (Calculation)-0.230.230.23
Speed (rpm)1002352
20046112
30070164
40092225
500115276
600138328
700162388
Gear Ratio (From Data)-0.230.050.01
Gear Efficiency-0.870.840.87
TABLE 3 : 4 Stage Gear with Same Size Gear Gear Set 2
Gear 0
( Motor )
Gear 1
Gear 2
Gear 3
No of teeth (t)183878118
Pitch Diameter (D) mm3676156232
Gear Ratio (Calculation)-0.470.230.15
Speed (rpm)10048122
20095234
300143345
400189426
500237557
6002856611
7003327814
Gear Ratio (From Data)-0.230.050.01
Gear Efficiency-0.870.870.87
Gear with different size make motor speed (Rpm) increase.
The value is not accurate and very sensitive to define. Speed motor with same size or different size with Gear 0 to 3, the value of speed motor from result will decrease until the lowest value in the data from Gear 0 to Gear 3DISCUSSIONS :i. From table 1 and 2, calculate the gear ratio theoretically and experimentally and compare the result. From the data, the value from table 1 and 2 shows that the gear ratio of
calculation and the gear ratio of theory are different.
It show that data with experimentally, that motor speed is higher than data
With theory.it because depending with the size and teeth that we use to
Experiment
Gear Ratio (Calculation)0.230.230.23
Gear Ratio (From Data)0.230.050.01
Gear Ratio (Calculation)0.470.230.15
Gear Ratio (From Data)0.230.050.01
ii. From the experiments, plot the graph Speed (rpm) versus Time (seconds) of the Gear set 1 and 2. Review the results.iii. What are the input torque and the output torque of the gear system. Given that the input power Pin equal to 20kW and the efficiency, equal to 0.7.Gear 0Gear 1Gear 2Gear 3
N (rpm)(Rad/sT (Nm)N (rpm)(Rad/sT (Nm)N (rpm)(Rad/sT
(Nm)N
(rpm)(Rad/sT
(Nm)
10010.471910.2232.4088305.650.52438167.920.20995693.7
20020.94955.10464.8174152.0111.15217361.120.20995693.7
30031.426365.3707.3302728.5161.67511940.240.41847846.8
40041.89476.42929.6342076.0222.3038684.350.52438167.9
50052.36381.9711512.041661.1272.8277074.660.62831847.1
60062.83318.3213814.451384.1323.3515968.480.83723894.8
70073.30272.8516216.961179.2383.9795026.480.83723894.8
Table 1: 4 stage Gear with same size Gear - Gear Set 1The value taken from data Table 1
Calculation For (() Gear 0
Formula : 2N/60
2 x x 100 =10.47 rad/s
60 Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/10.47
= 1910.2 Nm (input Torque)
The value taken from data Table 1
Calculation For (() Gear 1
Formula : 2N/60
2 x x 23 = 2.408 rad/s
60
Calculation Tork (T) ,Given data input power =20kW
T=P/(T= 20kW/2.408
= 8305.6Nm (Output Torque)
The value take from data Table 1
Calculation For (() Gear 2
Formula : 2N/60
2 x x 5 = 0.524 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/0.524
= 38167.9 Nm (Output Tork)
The value take from data Table 1
Calculation For (() Gear 3
Formula : 2N/60
2 x x 2 = 0.209 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/0.209
= 95693.7 Nm (Output Torque)Gear 0Gear 1Gear 2Gear 3
N (rpm)(Rad/sT (Nm)N (rpm)(Rad/sT (Nm)N (rpm)(Rad/sT
(Nm)N
(rpm)(Rad/sT
(Nm)
10010.471910.2485.0263979.3121.25615915.520.20995693.7
20020.94955.10959.9482010.5232.4088305.640.41847746.5
30031.426365.314314.971336.0343.5605617.950.52338197.1
40041.89476.4218919.791010.6424.3984547.560.62831847.1
50052.36381.9723724.82805.8555.7603472.270.73327285.1
60062.83318.3228529.85670.0666.9112893.9111.15217362.3
70073.30272.8533234.76575.37788.1682448.5141.46613641.8
Table 2: 4 stage Gear with Different size Gear - Gear Set 2
The value take from data Table 2
Calculation For (() Gear 0
Formula : 2N/60
2 x x 100 =10.47 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/10.47
= 1910.2 Nm (input Torque)
The value take from data Table 1
Calculation For (() Gear 1
Formula : 2N/60
2 x x 48 = 5.026 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/2.408
= 3979.3 Nm (Output Torque)
The value take from data Table 1
Calculation For (() Gear 2
Formula : 2N/60
2 x x 12 = 1.256 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T=P/(T= 20kW/0.524
= 15915.5 Nm (Output Torque)
The value take from data Table 1
Calculation For (() Gear 3
Formula : 2N/60
2 x x 2 = 0.209 rad/s
60
Calculation Torque (T) ,Given data input power =20kW
T= P/(T= 20kW/0.209
= 95693.7 Nm (Output Torque)
iv. Calculate the efficiency of the gear system (gear set 1 and 2) of the following combination gear :-a. Gear 1 to gear 0
b. Gear 2 to gear 0
c. Gear 3 to gear 0Set 1Gear 0 Gear 1Gear 0 Gear 2Gear 0 Gear 3
N (rpm)Gear Ratio =efficencyGear Ratio=efficencyGear Ratio=efficency
1000.231.00.051.00.021.0
2000.231.00.061.00.021.0
3000.230.10.050.10.010.1
4000.231.00.061.00.011.0
5000.231.00.050.80.011.0
6000.231.00.051.00.011.0
7000.231.00.051.00.011.0
Average Gear ratio0.23-0.05-0.01-
Average Effeciency-0.87-0.84-0.87
Set 2
Gear 0 Gear 1Gear 0 Gear 2Gear 0 Gear 3
N (rpm)Gear Ratio =efficencyGear Ratio=efficencyGear Ratio=efficency
1000.231.00.051.00.021.0
2000.231.00.061.00.021.0
3000.230.10.050.10.010.1
4000.231.00.061.00.011.0
5000.231.00.051.00.011.0
6000.231.00.051.00.011.0
7000.231.00.051.00.011.0
Average Gear ratio0.23-0.05-0.01-
Average Effeciency-0.87-0.87-0.87
CONCLUSION :
From the experiment, the objectives have been achieved which are describing the different types of gear system, calculating the ratios, angular velocity, input and output speed and efficiency. REFERENCES :
http://en.wikipedia.org/wiki/Gear McGraw Hill Encyclopedia of Science and Technology, "Gear" Gear Dive Systems: Design and Application, by Peter Lynwander
N1
Control Panel
Unit of Gear set
Protective transparent cover
Main Table
Motor Display
Figure 2 : Connection Diagram
Computer
Motor Driver
Speed Set
Gear Set
Potentiometer
Motor
Computer
Control Panel
Protective transparent
CPU
Table
Gear Set
Main Table
N2
SET 1
SET 2