Group 6 - Mini-Bike - Revision history

MAE277 06 09 at 13:50, 16 December 2009

2009-12-16T13:50:51Z

MAE277 06 09 at 13:43, 16 December 2009

2009-12-16T13:43:27Z

MAE277 06 09 at 23:12, 15 December 2009

2009-12-15T23:12:32Z

MAE277 06 09 at 22:54, 15 December 2009

2009-12-15T22:54:06Z

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MAE277 06 09 at 22:47, 15 December 2009

2009-12-15T22:47:45Z

MAE277 06 09 at 20:28, 15 December 2009

2009-12-15T20:28:13Z

MAE277 06 09 at 20:24, 15 December 2009

2009-12-15T20:24:30Z

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MAE277 06 09 at 17:06, 15 December 2009

2009-12-15T17:06:28Z

MAE277 06 09 at 17:00, 15 December 2009

2009-12-15T17:00:54Z

MAE277 06 09 at 17:00, 15 December 2009

2009-12-15T17:00:26Z

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 ==Introduction==
-This project is a formal
+This project is a formal reverse engineering study of a mini-bike. The project is meant to enhance the group's technical writing skills, engineering analysis, website design and teamwork.<br>
 ==Executive Summary==
 The objective of this project is to better understand the product through dismantling, modeling and reassembly. The product is a mini-bike not yet out on the market. It is designed only for recreational uses. Its top speed is approximately 10 mph. It stands up well without any external support and with its wide tires and low center of gravity is very stable even at very low speeds. The throttle is in the very convenient position of the right handlebar grip. The throttle signals the fuel air mixture flow mass flow rate to increase converting chemical energy to reciprocating mechanical energy and waste thermal energy in the combustion chamber then the reciprocating mechanical energy is turned into rotational mechanical energy by the clutch and transferred through the chain to the rear axle where the rear wheel in combination with the surface it rests on turns that rotary motion into linear motion.

@@ Line 1: / Line 1: @@
 [[Image:MB2.jpg|thumb|right|500px|Mini-Bike Side View]]
+==Introduction==
 ==Executive Summary==
-The objective of this project is to better understand the product through dismantling, modeling and reassembly. The product is a min-bike not yet out on the market. It is designed only for recreational uses. Its top speed is approximately 10 mph. It stands up well without any external support and with its wide tires and low center of gravity is very stable even at very low speeds. The throttle is in the very convenient position of the right handlebar grip. The throttle signals the fuel air mixture flow mass flow rate to increase converting chemical energy to reciprocating mechanical energy and waste thermal energy in the combustion chamber then the reciprocating mechanical energy is turned into rotational mechanical energy by the clutch and transferred through the chain to the rear axle where the rear wheel in combination with the surface it rests on turns that rotary motion into linear motion.
+The objective of this project is to better understand the product through dismantling, modeling and reassembly. The product is a mini-bike not yet out on the market. It is designed only for recreational uses. Its top speed is approximately 10 mph. It stands up well without any external support and with its wide tires and low center of gravity is very stable even at very low speeds. The throttle is in the very convenient position of the right handlebar grip. The throttle signals the fuel air mixture flow mass flow rate to increase converting chemical energy to reciprocating mechanical energy and waste thermal energy in the combustion chamber then the reciprocating mechanical energy is turned into rotational mechanical energy by the clutch and transferred through the chain to the rear axle where the rear wheel in combination with the surface it rests on turns that rotary motion into linear motion.

← Older revision		Revision as of 23:12, 15 December 2009
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	[[Image:MB2.jpg\|thumb\|right\|500px\|Mini-Bike Side View]]		[[Image:MB2.jpg\|thumb\|right\|500px\|Mini-Bike Side View]]

−
−	~~== Group Members ==~~
−	*'''Jeffrey Becker''' - Communication Liaison
−	*'''Stephen Harris''' - Group Leader/Wiki Manager
−	*'''Eric Jongsma''' - Solid Model Creator
−	*'''Garth Lester''' - Technical/Mechanical Expert
−	*'''Eddie Morales''' - Technical/Mechanical Expert

	==Executive Summary==		==Executive Summary==

← Older revision		Revision as of 22:47, 15 December 2009
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	Discussion of Results: The scenario for failure of the group 6 mini-bike was the failure of the brake cable. As shown in the calculations the ultimate tensile force that the steel cable can withstand is 1505.2 N while the ultimate tensile force the cable will experience is only 140 N. The safety factor calculated for this problem of 10.75 means that under the assumed conditions there will be no failure of the specified component in the specified way. The limitations to this solution are numerous. The assumed hand force applied is only a rough guess given some slight experimentation meaning the maximum force could be higher especially since humans have a wide range of strengths. The distance and position over which the hand force is applied in reality would vary widely for different sized hands and grips though the distance and position assumed in this problem is a pretty common one for a standard brake grip (determined though life experience on bikes with friends and family). The exact material of the cable is unknown however the steel ultimate tensile strength used is a relatively low and common one so a reasonable maximum tensile force should have been obtained. This evaluation of the ultimate tensile force applied vs the ultimate tensile force that the cable can withstand would be improved by better knowledge of the geometry of the cable at its ends.		Discussion of Results: The scenario for failure of the group 6 mini-bike was the failure of the brake cable. As shown in the calculations the ultimate tensile force that the steel cable can withstand is 1505.2 N while the ultimate tensile force the cable will experience is only 140 N. The safety factor calculated for this problem of 10.75 means that under the assumed conditions there will be no failure of the specified component in the specified way. The limitations to this solution are numerous. The assumed hand force applied is only a rough guess given some slight experimentation meaning the maximum force could be higher especially since humans have a wide range of strengths. The distance and position over which the hand force is applied in reality would vary widely for different sized hands and grips though the distance and position assumed in this problem is a pretty common one for a standard brake grip (determined though life experience on bikes with friends and family). The exact material of the cable is unknown however the steel ultimate tensile strength used is a relatively low and common one so a reasonable maximum tensile force should have been obtained. This evaluation of the ultimate tensile force applied vs the ultimate tensile force that the cable can withstand would be improved by better knowledge of the geometry of the cable at its ends.
−
−	~~==Reassembly==~~
−	1. Cylinder head and gasket: 6 bolts, 10mm socket wrench: when tightening the head back on, a torque wrench should be used to a specific torque specified by the manufacturer. But since we did not have one, we tightened them to the best of our abilities.<br>
−	~~a. Spark plug: 19mm socket wrench<br>~~
−	b. Spark plug cover + timing mechanism: 2 - 10mm bolts for the timing mechanism: It was difficult to adjust the timing mechanism to the proper position. The mechanism itself is magnetic and it hovers over the magnetic flywheel and is held on by 2 bolts. In order to secure it, you have to hold the mechanism over the magnetic flywheel, which can be difficult.<br>
−	2. Carburetor and gaskets: 2 – 8mm bolts. The carburetor slides onto 2 rails , with a gasket on the inside and the outside. Since the gaskets were specific to there respective side, it took a minute to figure out which one went where.<br>
−	~~3. Air filter: 2 – 8mm bolts. The air filter went on the outside of the carburetor on the same rails that the carburetor slid onto.<br>~~
−	4. Throttle assembly: This was the most difficult part of the reassembly process. This was due to the fact that there were 2 springs that attached to the motor in different points, and we referred to pictures to see where they attached.<br>
−	5. Muffler and gasket: 2-8mm socket wrench: This also includes the muffler cage. One of the springs of the throttle assembly was attached to the muffler cage to keep the assembly in proper tension.<br>
−	~~6. Starter assembly: 3-9mm socket bolts: The starter assembly goes on the opposite side of the clutch and flywheel, which turns the motor over.<br>~~
−	7. Gas tank and shield: 10 mm , 3 bolts : The shield goes under the gas tank which keeps the heat of the engine from heating up the gas in the tank. We also had to make sure we hooked up the gas line tube from the tank to the engine.<br>
−	8. Kill switch: The kill switch has 2 wires that attach to the motor at 2 different points. One is a ground that bolts directly to the engine block and the other attaches to the timing mechanism. At this point, all the components that attach to the motor are secured.<br>
−	~~9. Rear wheel assembly: <br>~~
−	~~a. Sprocket: 6 bolts, 5mm hex wrench. The sprocket goes on the left side of the wheel and the bolts have to be tightened in a star pattern with a torque wrench.<br>~~
−	~~b. Brake rotor: 6 bolts, 5mm hex wrench. Is secured on the same way as the sprocket in a star pattern.<br>~~
−	~~c. There are 2 different size spacers. The larger of the 2 goes on the left side, or the drive side, while the smaller of the 2 goes on the right.<br>~~
−	~~d. There is a 14mm bolt that is secured on with a lock nut.<br>~~
−
−	~~10. Steering wheel & handlebar assembly: <br>~~
−	~~a. A large 14mm bolt goes through the top of the assembly and is secured on by a 16 mm nut on the bottom of the headset.<br>~~
−	~~b. The brake lever is reattached using a 5mm hex wrench and the cable is fed through at the top of the handle.<br>~~
−	~~c. The throttle is attached to the right side of the handle bars and is secured using a 3mm hex wrench.<br>~~
−	d. Rear fender: There are 2 bolts with rubber washers that attach the fender on. The rubber washers go in between the mounts and the bolts to prevent chattering noise when the fender is vibrating.<br>
−	~~11. 2 Chain Guards: the chain guards cover the path of the chain for the safety of the rider. The rear chain guard goes on first, and then the front chain guard overlaps it.<br>~~
−	~~12. Seat: There are 3 – 10mm bolts that secure the seat<br>~~
−
−	~~==Post Reassembly analysis==~~
−	~~<b> Reassembly Process note</b>~~
−	~~<blockquote> All the same tools were used to reassemble the product as were used in its dissassembly</blockquote>~~
−	~~<b> End Result of Reassembly notes</b>~~
−	<blockquote>After Reassembly the bike no longer works. The problem with the bike appears to be related to the throttling assembly which unfortunately no longer function properly due to the fact that at one of its pivot points it is missing a piece to hold it on. To correct the problem our group suggest looping a metal ring through the throttle assembly and the pin on that pivot to prevent the throttling device form popping off.<blockquote>
−	~~<b> Product Recommendations</b>~~
−	~~Our main recommendation concerning the product given our trouble with the reassembly is to make the throttling assembly more robust.~~

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 -Engineering Analysis</b><br>
 [http://gicl.cs.drexel.edu/wiki-data/index.php?title=Group_6_-_Mini-Bike/CoPR Coordination Project Review Page]
 ==Component Summary==
 Muffler:<br>

@@ Line 18: / Line 18: @@
 -Initial Product Assessment</b><br>
 [http://gicl.cs.drexel.edu/wiki-data/index.php?title=Group_6_-_Mini-Bike/RFP Request of Proposal Page]
 ==Causes for Corrective Action==

@@ Line 16: / Line 16: @@
 -<b>Work Proposal<br>
 -Management Proposal<br>
--Initial Product Assessment<\b><br>
+-Initial Product Assessment</b><br>
 [http://gicl.cs.drexel.edu/wiki-data/index.php?title=Group_6_-_Mini-Bike/RFP Request of Proposal Page]