Group 11 - Beginner Dirt Bike

Revision as of 14:13, 7 December 2009

Group 11 - Gate 1

Group 11 - Gate 2

Gate 3: Coordination Review

Component Summary

Part Numbers were found using the online product owners manual. The are specific to our brand of dirt bike. In parts that are assemblies, part numbers are for the main product of the assembly.

The complexity rating is a rating of 1 to 5. 1 being the easiest to manufacture, while 5 is the most difficult. Our ratings are based on the groups assumptions of the number of steps it takes to assemble each part.

Photos will be uploaded when the website picture uploading capabilities resume. Till then we are sorry for any inconvenience.

Thank You.

Dirt Bike Parts List

Part and Quantity	Part Number	Function	Materials	Forces	Manufacturing Process	Shape	Part Complexity	Photo
Engine Cover (2)	DR70-118	Functional/cosmetic: This part is a combination. It is used to cover and protect the engine from the rider and debris. It also hides the less attractive parts of the engine	Metal, probably aluminum because of its light weight	No forces exerted	Die Casting because of its fine surface finish and the residual risers	Rounded edges and hollowness of part lends itself to die casting	1
Gas Tank (1)	DR70-147	Functional: storage place on dirt bike to hold fuel	Main tank is plastic because it is light weight and will not react with the fuel. The hose is rubber to allow it to move	The force from the fuel weight would be 5 lbs or less. The forces exerted on the frame would be in equilibrium	Plastic blow molding because it is a hollow plastic container. Drilling would then be done for holes.	Seams along the edges lend to blow molding. The shape allows for maximum storage in the space allotted.	2	Error creating thumbnail: convert: Insufficient memory (case 4) `/export/gicl/website/htdocs/mediawiki-repo/images/thumb/6/6e/Gas_Tank.jpg/2448px-Gas_Tank.jpg' @ error/jpeg.c/EmitMessage/235.
Handle Bars (1)	DR70-136	Functional: Allows rider to steer the bike. Also gives rider something to hold onto while riding	Main frame is metal, probably aluminum because it is light weight. Handles are rubber for a better grip.	Only forces exerted would be those exerted by rider.	For main ‘U’ tubing is heated then bent into shape. Then horizontal bar is welded into place	Shape lends itself to comfort of use. Also shape leans itself to ease of production	3
Engine Block (1)	DR70-117	Functional: Takes the fuel provided and turns into in to forward motion, by the use of chemical combustion	Metal is used, probably aluminum for its strength and durability. Some parts might require steel for even more strength.	The only major forces are those within the engine. These forces would be the result of the fuel combusting and moving within the engine. These forces are equal to the power that drives the bike.	This part is an assembly of many different processes. There would be die casting for the main part. Drilling would be done for several connecting holes. Several parts have been welded on as well	The shape lends itself to many different processes because it is so complex. No single process could create the engine block as a whole. The side gears and rotating parts would need to be separately made then assembled	5
Front Fender (1)	DR70-137	Functional: Protects rider from debris. Color of part is cosmetic to give bike an overall color scheme	Plastic is used to be light weight.	The only forces acting would be if something where to hit this part. The force would then depend on the object and the speed of the bike	Injection Molding because of its symmetrical look and risers on underside of part	The part is formed to follow the contour of the wheel to proved extra protection for the rider	1
Frame Cover (1)	DR70-100	Functional/cosmetic: Provide comfortable riding while protecting rider from engine and the engine from debris. Color is cosmetic.	Mostly plastic with seat being foam padding with fake leather covering	Only forces would be the weight of the rider. This should be 165 lbs or less.	Plastic molding, probably injection molding	Several parts were formed separately then connected together through screws.	3
Kick Stand/Foot Pegs (1)	DR70-090	Functional: place for rider to place feet when moving and Holds up bike when stationary	Metal, probably aluminum because it is light and strong.	Forces would be a portion of the rider’s weight. The kick stand would support the bike weight -132 lb	Die casting for foot pedals, bending for main bar. Welding and other forms of metal casting for side parts	This part is an assembly of other smaller parts. The parts need to be able to move separately causing them to be manufactured separately.	4
Electrical Cables (1)	DR70-129	Functional: Transfers electricity to spark plug to start engine	Wiring is metal, probably copper. Outside is rubber. Connectors are plastic.	No forces would be applied.	Metal wiring, most likely copper, is cold drawn into desired shape. Rubber housing is wrapped around as an insulator. Plastic ends are plastic injection molded	The shape of this part is determined by two specifications. First is what is needed by the bike for the electrical supply. The other is how the different components are assembled together	3
Rear Shock (1)	DR70-116	Functional: absorbs forces caused by movement over uneven terrain	Metal spring; probably steel for strength and resistance. This is coated in rubber housing.	Forces applied would depend on the weight of the rider and the motion of the bike	Metal is twisted in a spiral to create spring. Spring is then coated in rubber to protect it. Ends are milled and drilled to create space to for attachment	Shape is defined by the requirements of the shock. A shock designed to absorb 100 lb of force compared to 200 lb of force would be very different, in size and thickness of spring	4
Muffler System (1)	DR70-124	Functional: Takes exhaust from engine and releases it at the rear of the bike. Helps to minimize noise from the engine.	Whole part is metal, most likely steel. Steel would be used because of its high strength and cheap cost	The only forces applied would be the air flowing through the system. On straight parts, this would result in very little force. Where the tubing turns, the forces would depend on the pressure, temperature, and velocity of the exhaust	The main system was manufactured by heating steel tubing and then bending it. The outer pans where metal extrusions and then bending. These parts were then welded together.	The shape is needed to do the purpose. The turns are needed to slow the velocity of the air. The length of the part is also needed to make sure the exhaust is directed far enough from the engine and the rider.	3
Gear Shift (1)	DR70-125	Functional: Allows rider to shift gears while riding bike	Mostly metal, probably aluminum because of its light weight	The only force would be those applied when the rider shifts gears. Thus the force would only be the a percentage of the rider strength	Several parts created, the welded together. This can be seen because of welding marks near joints. The two end pieces are just metal tubing, while the middle is bent metal.	The shape is dictated by two things. The first is to allow enough torque to change gears, with little force needed from the rider. Also the shape is designed for comfort of the rider, with there being no sharp edges.	2
Steering Shaft Assembly (1)	DR70-197	Functional: Attaches to the handle bars and the front wheel assembly to allow rider to steer. Also holds the front forks, front shock absorbers.	Metal, most likely steel composite because it is lighter than other steel part, but strength is needed for this part.	Force would be created as the rider turns the handlebars. Depending on terrain there could be resistance to this motion. Also since this secures the shocks, it would get force from that.	Parts are created then assembled. The two bases are die-cast, because of left over risers. Several parts are then drilled, and threaded. Parts are then assembled by nuts or screwed together.	Shape is needed for several reasons. First is that the parts are rounded, because die casting straight edges is difficult. Also this is a part that the rider could hit, and straight edges could cause injury.	4
Chain (1)	DR70-046	Functional: used to connect the engine to the rear wheel, and transfer energy between the two.	Metal, most likely steel for its strength and resistance to wear because of friction	There would be a friction force between the chain and the gears. There would also be a tension force between the chain links.	Individual chain links pinned together with the correct spacing needed for the gears used to create a flexible belt.	Shape and size is determined by several factors. One is the spacing between the engine and the wheel. The spacing of the links is determined by the gears that are being used.	4
Rear Frame (1)	DR70-107	Functional: connects back tire to the rest of the bike.	Metal, most likely aluminum , because of its light weight.	There would be two forces applied to it. The first would be horizontal, in keeping the wheel vertical. The other would be a portion of the bike’s and rider’s weight.	Square metal tubing is heated and bent into the needed shape. The cross bar is welded onto these parts. Holes and slots are then drilled into the part.	Specific Shape is needed because of the forces applied to it. Must be able to distribute weight and not break.	4
Front Shocks (2)	DR70-114	Functional: Absorbs vibration from the front wheel to provide a smooth ride for the rider.	Metal tubing with a metal piston. The air chamber inside the tubing is pressurized.	Forces caused by vibration and sudden changes in height. Shocks absorb forces because of weight from bike and rider.	Two cylindrical tubes connect to each other with the smaller one being underneath the larger one. This allows for the smaller tube to fit inside the larger tube where forces are eliminated with the use of an air pocket.	Cross sectional area and dimensions of the air chamber depend on the desired force to negate.	4
Front Brake Cable (1)	DR70-366	Functional: Connects the hand brake to the wheel	Rubber housing covering a metal cable, steel for strength so that it doesn't brake	Forces caused by rider when the rider engages the brake	Steel cold pressed into wire of desired shape. Rubber covering to prevent friction	Shape can change and is formed to connect the hand brake with the wheel brake without the cable affecting other components	2
Frame (1)	DR70-100	Functional: Holds components of bike together	Metal steel mixture so that it is light but has steel for strength	Forces are the weight of the bike and the rider along with the vibrations that were not absorbed by the shocks	Metal tubing heated then bent to create shape of bike along with some welding to connect joints	Shape is formed to connect all components of the bike while still creating a comfortable riding position	2
Rear Sprocket (1)	DR70-381	Functional: Connects chain to the rear wheel	Metal/steel for strength	Force of engine driving the chain which transfers force to drive the wheel	Pressed into correct shape	Shape has multiple pegs evenly spaced to fit into the links on the chain	2
Brake Pedal (1)	DR70-406	Functional: Transfers force of rider to the rear brake	Metal, aluminum for less weight	Force of rider when rider engages the rear brake	Metal tubes bent and welded. Foot peg is molded	Shape has pointed edges to eliminate the rider's foot from slipping off the brake	2
Rear Brake (1)	DR70-402	Functional: Presses shoes against brake drum creating friction to stop the bike	Metal, steel for strength	Frictional forces needed to slow bike	Die-casting	Circle shape with two "half moon" shaped shoes	4
Number Plate (1)	DR70-143	Cosemetic: Provides a smooth surface for a racing number to be placed	Plastic	Force of air resistance when bike is in motion	Molded to create correct shape	Square shape with rounded edges	1
Front Axel (1)	DR70-159	Functional: Connects the front wheel to the front forks while still allowing the wheel to freely rotate	Metal, steel for strength	Force that the weight of the rider and bike exert on the front wheel	Extruded and then threaded	Long cylinder which fits directly in the center of the front wheel	1

Design Revisions

First Revision

Braking system from drum brakes to disk brakes.

Reason

Drum brakes are more inefficient than disk brakes because they trap heat within themselves and lose their efficiency as they heat up. This is because the trapped heat causes the pads to expand which makes them not rub against the drum around them using its whole surface area, losing braking power. Disk brakes allow for free flow of air around them and continually cool off as they are used, so they maintain their stopping ability with a minimal if any loss in efficiency. Disk brakes are also easier to replace and maintain.

Second Revision

Cable lines converted to hydraulic line system.

Reason

Cable lines rub against their protective coating on the majority of the cable itself. This friction greatly reduces the amount of braking force that could be applied if there was no friction. Hydraulic lines have almost no friction and the fluid used in the lines cannot be compressed, so there is virtually no loss in power.

Third Revision

All bolts in standard sizes.

Reason

Disassembly was more complicated than it needs to be because of the time spent searching for tools because half of the dirt bike is assembled in standard and the other half in metric. Also if the company used all the same size or close to the same size bolts in most places the assembly cost would go down because ordering bolts in bulk in abundant sizes would be cheaper and each part on the assembly line could use the same tool to attach their part of the dirt bike.

Solid Modeled Assembly

Our solid modeling assembly was that of the steering column. Please follow the link to a picture of the exploded view. When picture uploading resumes on this website, we will post this picture and more up on our web.

Thank you.

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Engineering Analysis

First Revision

Braking system from drum brakes to disk brakes.

Assumptions

-Weight of overall dirt bike is the same for both braking types -Speed, and stopping force applied are the same in both cases initially -Coefficient of friction is the same for all brake pads and shoes

Governing Equations

P=F/A

A= ((Pi)*r^2*w)/2

F=m*((Vf-Vo)/t)

Calculations

F=209.5 N with m=70.3kg and Vo=8.94 m/s Vf=0 m/s at 3 seconds

Disk:

A=2e-4m (cold)

A=2.8e-4m (heated)

Pcold<=Pheated because of expansion From heating

P=748214.2857 N/m

Drum:

A=2e-4m (cold)

A=2.8e-4m (heated)

Pcold>Pheated because of deformation due to expansion from heating

P=561160.7143 N/m

Discussion:

Drum brakes are more inefficient than disk brakes because they trap heat within themselves and lose their efficiency as they heat up. This is because the trapped heat causes the pads to expand which makes them not rub against the drum around them using its whole surface area, losing braking power. Disk brakes allow for free flow of air around them and continually cool off as they are used, so they maintain their stopping ability with a minimal if any loss in efficiency. Disk brakes are also easier to replace and maintain.