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 !

Maskinkonstruktion MF2005 & MF2006 Innovativ konstruktion Sida 2(15) KTH Tenta 2013-01-08, Del 1

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 3(15) KTH Exam 2013-01-08, Part 1

Part 1:

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)

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 4(15) KTH Exam 2013-01-08, Part 1

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)

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 5(15) KTH Exam 2013-01-08, Part 1

5. Give three ways that you can arrange the tension in a belt drive. (3p)

6. Enumerate the parameters having the greatest influence on the transmittable torque in a belt transmission. (3p)

7. Name three different types of hydraulic motors / pumps (3p).

8. Suggest four ways to avoid the nut to loosen in a bolted joint. (2p).

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 6(15) KTH Exam 2013-01-08, Part 1

9. Suggest a stiffening of this design in the loaded direction. Sketch three different stiffening solutions. (3p)

10. Give three examples of how to arrange for lubrication of a chain transmission. (3p)

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 7(15) KTH Exam 2013-01-08, Part 1

11. A component is shown in the figure above (4p)

a. What is A pointing at? _______________________________________________________

b. What is B pointing at? _______________________________________________________

c. What is C pointing at? _______________________________________________________

d. What kind of machine element is this? _______________________________________________________

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 8(15) KTH Exam 2013-01-08, Part 1

12. You must transmit a torque of 5 Nm to a hub with a friction joint

Which surface pressure is required in the joint, when µ=0,3, Ri=15mm, Ry=25mm and l= 30mm? (4p)

13. You want a clearance fit that varies between 0,07 and 0,12 mm, (3p)

the dimension of the hole is ∅50 � 0−0,02�

give the tolerances for the shaft____________________________________________

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 9(15) KTH Exam 2013-01-08, Part 1

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)

NOTE: The body is rotationally symmetric (4p)

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 10(15) KTH Exam 2013-01-08, Part 1

MF2005 & MF2006 Innovative design Exam Tuesday January 8, 2013

Part 2 Part 2 include 36p

Time: 9.00 -13.00

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

ANSWER THE QUESTIONS ON A SEPARATE PAPER!

START ON A NEW SHEET FOR EACH QUESTION !

DON’T WRITE AT THE BACK OF THE PAPER !

GOOD LUCK !

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 13(15) KTH Exam 2013-01-08,Partl 2 DEL 2 :

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)

Describe the assumptions you make!

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 14(15) KTH Exam 2013-01-08,Partl 2

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

Report your assumptions!

Maskinkonstruktion MF2005 & MF2006 Innovative Design Sida 15(15) KTH Exam 2013-01-08,Partl 2

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!

1000 mm 100 mm