MF 2005 & MF2006 Innovative design Exam Tuesday January 8, 2013 Part 1 Time: 9.00 - 13.00 This exam consists of two parts: Part 1: Short questions (44p) Allowed aids: Writing and drawing materials, calculator ANSWER IN THIS BOOKLET ! Part 2: Investigating questions which require engineering based considerations (36p) Allowed aids: The book “Maskinelement” by Karl-Olof Olsson, The book “Machine Elements in Mechanical Design” by Robert L.Mott, Maskinelement handbok, Formulas in solid mechanics, Karlebo handbok Part 2 is given to you when you submit part 1 Name Personal nr Signature No of separete sheets: GOOD LUCK !
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This exam consists of two parts: Part 1: Short questions (44p) Allowed aids: Writing and drawing materials, calculator ANSWER IN THIS BOOKLET ! Part 2: Investigating questions which require engineering based
considerations (36p) Allowed aids: The book “Maskinelement” by Karl-Olof Olsson, The book “Machine
Elements in Mechanical Design” by Robert L.Mott, Maskinelement handbok, Formulas in solid mechanics, Karlebo handbok
1. David Smith has in his book ”Exploring Innovation” classified innovations based on two main types of knowledge needed to create a product. These two types are system knowledge and component knowledge. Four different types of innovations can then be classified based on changes of components and/or system. Two of these can be illustrated by the so called ”Technology S-curve” shown below. Which are these two types and how can we se it in the figure? (3p)
2. Sketch the torque as a function of the speed of an (AC ) induction motor. Mark interesting torque levels and the operation point on the graph. (3p)
3. Pre tensioning of the bolted joint in fig a below gives a force-deformation relation according to fig b. We decide to change the bolt dimension to a weaker dimension, e.g. from M10 to M8. Draw a graph of the new force-deformation relation (in principle). Illustrate in the graph how an external applied force is distributed on the bolt resp. flange? (3p)
Skruv Fläns
Kraft
Deformation
δs δf
b
4. Give three solutions of axially locking of a single row deep groove ball bearing on a shaft. (3p)
14. The drawing view shown below is an incomplete cut view of a rotationally symmetric part. Add a view of the original part to the right with cut lines and add also missing things like centerlines in the current view.
Dimension the two detail views (surface finish and tolerances are not needed)
I. An ordinary electric mixer shown in the sketch below. It consists of an electric motor and a transmission down to the two counter-rotating beaters. The electric motor is mounted as symbolically drawn in the figure below (A).
The task is to construct the transmission from the engine to the beaters (box B). You should present sketches (with dimensions) of the main components of transmission, including shafts and bearings. (12p)
II. A pipe coupling for connecting pipes with an inner pressure of 10 MPa has been design and is illustrated principally in the figure below. The coupling will be sealed using an o-ring placed in a slot on one of the two halves. The main dimensions are shown in the right part of the figure. OBS, the number of holes in the figure should not be seen as a final design, it is part of this task to suggest the number of bolts for this flanged joint. (12p) .
Figure. Pipe coupling, left and main dimensions, right
Your task is to dimension the bolts in this bolted joint for the coupling. The pressure in the pipes can vary between 5-10 MPa. Given data: Outer pipe diameter 70 mm Thickness 5 mm Inner pressure 5-10 MPa Material SIS 1430, alt SIS 1330
III. A container with a hinged lid of 50kg is balanced using a counterweight, see figure below.
This container need to be placed close to a wall (1000 mm) that means that previous solution for balancing the heavy lid is impossible to use in this case and need to be redesigned.
Your task is to design a device/mechanism that can balance the lid of the container when it is placed 100mm in front of a wall, see figure below. Max weight of the device is max 100kg. The container can either have a circular or rectangular bottom, it´s up to you. Report your device, including modified container and lid, with dimensioned sketches and calculations, where it is clear how your design solution is functioning! (12p) Report your assumptions!