Recent content by Wilson123

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    Axial Thrust

    If I am designing my axle for a worse case scenario, I need to take this possible axial load into account? My initial thought that was when the user is going around a corner, a lot of the users weights and the weight of the wheelchair frame will be transfers down the axle and this would be my...
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    Axial Thrust

    I'm in the process of calculating my combined stress on an axle I am designing, I have calculated the bending and torsional stress, however I need to calculate the direct stress in the axle. In order to do this I need to know the axial thrust in my axle, I understand what axial force is but I am...
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    Steel tables for calculating axle diameter

    After looking over my calculations, I've realised I had my bending moment slightly too high, therefore my bending stress is wrong. My bending stress is actually 63MPa.
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    Calculating gear ratios for a drivetrain

    I took the rolling resistance from the below table taken from this link http://www.engineeringtoolbox.com/rolling-friction-resistance-d_1303.html Perhaps a higher one is more suited for rough terrain? Therefore, 75/3000=0.25 I want my answer to be 1.4 (walking speed), so I need to decrease...
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    Steel tables for calculating axle diameter

    No there isn't, my design has one axle per wheel, so the other wheel is supported by a mirror image of this axle.
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    Steel tables for calculating axle diameter

    Ah yes, I forgot to convert to MPa. I am familiar with deflection however not sure how to calculate it under these parameters, could you give me some pointers?
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    Steel tables for calculating axle diameter

    0.063kNm * 0.01m / 7.85398 x10-9m4 0.00063kNm2 / 7.85398 x10-9m4 80214kNm-2 (Not too sure on these units, what should they be?)
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    Steel tables for calculating axle diameter

    Thanks, I will do. Now that I have this bending stress for a 20mm diameter shaft, how do I decide if this is suitable for my application? Or do we now look at torsional stress?
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    Steel tables for calculating axle diameter

    Thank you. Second moment of area being calculated by pi/4 * r^4 ? By doing this I get 0.063 * 0.01 / 7.85398 x10-9 = 80214 as the bending stress?
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    Calculating gear ratios for a drivetrain

    What kind of information would be required to take rough terrain in account? Can you clarify why this would be at 0.25 m/s? I thought I was calculating the output power, and my initial calculation had found the output to be too high at 300N?
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    Steel tables for calculating axle diameter

    By maximum stress level is that the bending stress? which is My/I m= moment y= radius I = moment of intertia
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    Steel tables for calculating axle diameter

    1. Only the load shown in the previous diagram and this axle will be manually driven at low speeds. 2. Between 10mm and 23mm. 3. Preferably a stock bar sized would be used for the axle to keep costs down, so the closest one to the needed axle. 4. I am yet to select my bearings but only plan...
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    Calculating gear ratios for a drivetrain

    I've had a re-read through of the thread and answered most of my questions, thank you. I initially did the calculations using a gear ratio of 0.2m diameter for the driven and 0.1m diameter for the driver. I worked it out as getting an output of Fv=301.7N with the method you have shown. Looking...
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    Steel tables for calculating axle diameter

    Thanks for your help, I'll look into this ASAP. Regarding axial thrust, is there a way to determine what this load is for my circumstance? I understand it may not be a formula, just what factors I need to consider.
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    Calculating gear ratios for a drivetrain

    Thanks a lot for your help, I have a few questions regarding this method. 1. Am I correct in thinking I determine my own gear ratios to begin with and carry out the equations, deciding if my end result is correct and changing the ratio accordingly if required? 2. For calculating hand velocity...
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