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Homework Help: EML3005 Mechanical Design Project Shaft Analysis

  1. Nov 6, 2012 #1
    I need some help Desperately for this class.

    this project is 10% of my grade and i'm doing really bad in this class >_<.
    I have read the book but is all talking about is bunch of formulas that i have no idea how to relate them to this.
    I uploaded the diagram as well that was part of the Project information

    i don't want the answers necessarily but point me in the right direction
    X value=5
    Y value =8

    I uploaded the diagram explaining it a little bit more
    at the moment im confused as hell as to do what to do or where to even start from
    Code (Text):

    Assume that x is the second number in your UFID and that y is the fourth number.  
    (For example, if your UFID is 8765-4321, then x=7 and y=5.)

    See the sketches below.
    You have a shaft that is loaded by an overhanging V-belt pulley and a gear between the bearings.   The center of the pulley is  1x0 mm  from the center of the bearing.
    The belt tensions on the pulley are  y0o  above the opposite horizontal direction of the transmitted force (Wt) applied to the gear.
    The shaft transmits 10 kW at 1200 rpm.
    The pitch diameter of the pulley is 250 mm.  TB = 5TA.
    The involute gear is 20o, P=6, and has a pitch diameter of 6 inches.
    Assume the forces are in the centers of the gear, pulley, and bearings.

    Please create a report which includes the following:

    a.  a printed cover sheet with your name on it

    b.  shear and moment diagram for the shaft for the horizontal direction

    c.  shear and moment diagram for the shaft for the vertical direction

    d.  a diagram of the maximum bending moment at each point in the shaft

    e.  a diagram of the torque at each point in the shaft

    f.  (Doing no calculations at this time and assuming your design concepts may change after you do detailed design in Part B) sketch a conceptual design of the shaft.  The shaft sketch should show provisions for transmitting torque to the gear and pulley (keyways? holes? etc.) and methods for holding the components axially (shoulders? holes? snap ring grooves? etc.).  Assume (for now) that the pulley and gear have about 30 mm wide hubs and that the bearings are about 15 mm wide.  Put no dimensions on the shaft at this time, but the design should be reasonable.

    so far all i can think of is do FBD Diagram
    1st question would be what is the horizontal direction? is it the way is already drawn in the diagram or is that vertical direction?

    2nd question would be
    if i do a FBD the way is show there
    the reactions for Bearing,Gear,V pulley?

    By RA i mean Reaction at A for first bearing
    for Bearing is it only RAY i should take into account? or do i take into account RAZ?
    for the Gear is it only Torsion? that i take into account or does it have RAY and RAZ

    Any help would be Extremely appreciated

    Attached Files:

  2. jcsd
  3. Nov 12, 2012 #2
    I did some more work on it maybe somebody can help double check if im doing this calculations right

    WT=(60,000*H)/(π*D*N) H=power,KW D=gear diameter,mm N=speed rev/min
    information given shaft transmits 10KW at 1,200 rpm
    pitch diameter of gear 6inches since D has to be in mm i do conversion of
    6in*(25.4mm/1 in)=152.4 so D=152.4mm

    to find the normal force pushing on gear

    now im trying to solve for the pulley
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