Next Generation Automotive Sun Visor
Product Development
Nästa Generations Solskydd i Personbil Produktutveckling
Erik Torehov Ronnevik
Faculty of Health, Science and Technology
Degree project for master of science in mechanical engineering 30 hp
Supervisor: Mikael Grehk Examiner: Jens Bergström 2019-06-17
Abstract
The main purpose of the sun visor is to prevent the driver and passengers to get blinded by the sunlight. It is essential that the sun visor is not blocking the view and that the driver has a clear line of sight so that collisions can be prevented. However, the solution of today is limited as it only covers superior parts of the light and its functionality depends on the head position of the driver and passengers. Therefore, ÅF has initiated this thesis project to develop and improve the product with the goal to further prevent the driver and passengers from being blinded by the sunlight.
The scope of the project is to generate new concepts for the sun visor using product development methods.
The product development process involves various phases. Collecting and identifying customer needs and wishes resulted in a detailed requirement specification. Competitor analysis, or benchmarking, was conducted to create awareness of what already exists on the market. New concepts were created by two separate brainstorming sessions. These new concepts were evaluated by concept screening and concept scoring matrices and a final concept was chosen for further development.
The final concept was modeled and developed with all necessary components in CAD with help of the software Catia V5. A material selection was performed on the new components with help of CES Edupack and a final material suggestion for each component was presented.
The new sun visor consists of a sun curtain that is connected to profiles in the WEM cover and
the a-pillar. An electric motor in combination with a spring regulates the upward and downward
motion of the sun visor to a precise position. The driver or passenger can regulate the height of
the sun curtain by pushing a button. An advantage with the new design is that it eliminates the
leakage between the sun visor and the WEM cover and to the a-pillar. The designed sun visor does
not fit in the current interior of the driver compartment but has been created as close as possible
to fit the current space with only small adjustments to the interior. In addition, the components
of the new sun visor needs to be redesigned, mainly the WEM cover, to allow the new sun visor to
reach down to the lowest allowed point. The new concept has the potential to increase the visibility
more efficient than the standard sun visor.
Sammanfattning
Solskyddets huvuduppgift är att förhindra att föraren och passagerarna blir bländade av solljus.
Det är viktigt att solskyddet inte blockerar sikten samt att föraren har fri sikt så att kollisioner kan förebyggas. Dock är dagens lösning begränsad eftersom den endast täcker en viss del av det inkommande ljuset och dess funktion är beroende av huvudets position. Därför vill ÅF utveckla och förbättra dagens produkt till ett nytt koncept med hjälp av produktutvecklingsmetoder som förhindrar att föraren och passagerarna blir bländade.
Produktutvecklingsprocessen omfattar olika faser. Genom att samla och identifiera kundernas behov och önskemål kunde en detaljerad kravspecifikation erhållas. Konkurrensanalys genomfördes för att skapa medvetenhet om vad som redan finns på marknaden idag. Nya koncept skapades genom brainstormning. Dessa nya koncept utvärderades genom konceptscreening och konceptscoring och ett slutgiltigt koncept valdes för vidareutveckling.
Det slutgiltiga konceptet designades och utvecklades med alla ingående komponenter i CAD med hjälp av programvaran Catia V5. Ett materialval utfördes på de nya komponenterna med hjälp av CES Edupack och ett slutgiltigt materialvalsförslag för varje komponent presenterades.
Det nya solskyddet består av en gardin som är kopplad till profiler i WEM covern och a-stolpen. En
elektrisk motor i kombination med en fjäder kontrollerar solskyddets uppåtgående och nedåtgående
rörelse till en exakt position. Föraren eller passageraren kan reglera höjden på solskyddet genom
att trycka på en knapp. En fördel med det nya solskyddet är att läckage har eliminerats mellan
solskyddet och WEM cover samt a-stolpen. Det nya solskyddet får dock inte plats i den nuvarande
interiören men har designats så nära som möjligt för att passa i det aktuella utrymmet med endast
små ändringar av interiören. Dessutom måste vissa komponenter designas om, huvudsakligen WEM
covern, på grund av att gardinen inte går hela vägen ner till den lägsta tillåtna punkten. Det nya
konceptet har dock potential att blockera det inkommande ljuset effektivare än det nuvarande
solskyddet.
Table of contents
1 Introduction 1
1.1 Sun visor . . . . 1
1.2 ÅF Industry AB . . . . 2
1.3 Objective and purpose . . . . 2
1.4 Delimitations . . . . 2
1.5 Product Development . . . . 3
2 Analysis of current design 4 2.1 Functional content . . . . 4
2.2 Components . . . . 5
2.2.1 Body . . . . 7
2.2.2 Fixing points . . . . 7
2.2.3 Hinge . . . . 7
2.2.4 Frame . . . . 7
2.2.5 Sub frame . . . . 7
2.2.6 Vanity pack . . . . 7
2.3 Problem identification . . . . 7
3 Method 9 3.1 Identification of customer needs . . . . 9
3.2 Requirement specification . . . . 9
3.2.1 QFD . . . . 10
3.3 Competitor analysis . . . . 11
3.4 Concept generation . . . . 12
3.4.1 Formulation of the problem . . . . 12
3.4.2 Functional analysis . . . . 12
3.4.3 Creative methods . . . . 12
3.5 Concept selection . . . . 13
3.5.1 Concept screening . . . . 14
3.5.2 Concept scoring . . . . 15
3.6 Product design . . . . 16
3.7 Material selection . . . . 17
3.7.1 Translate design requirements . . . . 17
3.7.2 Screen using constraints . . . . 18
3.7.3 Rank using objective . . . . 18
3.7.4 Seek documentation . . . . 18
3.8 Future trends of sun visors . . . . 18
4 Results 19 4.1 Identification of customer needs . . . . 19
4.2 Requirement specification . . . . 19
4.2.1 QFD . . . . 20
4.3 Competitor analysis . . . . 20
4.3.1 Volvo V60 . . . . 20
4.3.2 Tesla Model X . . . . 22
4.3.3 Kia Ceed . . . . 24
4.3.4 SAAB 9-5 . . . . 25
4.4 Concept generation . . . . 27
4.5 Concept selection . . . . 31
4.5.1 Concept screening . . . . 31
4.5.2 Concept scoring . . . . 34
4.6 Product design . . . . 37
4.6.1 Shaft . . . . 40
4.6.2 Housing . . . . 41
4.6.3 Curtain . . . . 42
4.6.4 A-pillar . . . . 42
4.6.5 WEM . . . . 43
4.6.6 Roof . . . . 44
4.6.7 Snap hook . . . . 45
4.6.8 Wheel shaft . . . . 45
4.7 Material selection . . . . 46
4.7.1 Shaft . . . . 46
4.7.2 Housing . . . . 50
4.7.3 Curtain . . . . 51
4.7.4 A-pillar . . . . 51
4.7.5 WEM . . . . 52
4.7.6 Roof . . . . 52
4.7.7 Snap hook . . . . 52
4.7.8 Wheel shaft . . . . 52
4.8 Future trends of sun visors . . . . 52
5 Discussion 54 5.1 Product development . . . . 54
5.2 Product design . . . . 55
5.3 Material selection . . . . 55
5.4 Future trends of sun visors . . . . 55
6 Conclusion 56 6.1 Future work . . . . 56
7 Acknowledgments 57
References 58
Appendices 60
1 Introduction
Vehicle functionality is one of the leading segments in innovation and component development.
Despite this fact there is a component in the cockpit environment that has kept just about the same function design for various years - the sun visor. The main purpose of the sun visor is to increase visibility on the road by blocking the sunlight. However, the solution of today is limited as it only cover superior parts of the sun and its function is dependent on the head position of the driver and passengers.
The first chapter introduces the concept of a sun visor and the background of the company followed by objective, purpose and delimitations. It also contains an introduction about the subject product development.
1.1 Sun visor
The main purpose of the sun visor is to prevent the driver and passengers to get blinded by the sunlight. It is essential that the driver has a clear line of sight so that collisions can be prevented.
The first sun visor that were seen on the market was on a Ford model T in 1924 [1], see Figure 1.1.
The sun visor was part of the exterior which is quite different from what are seen today.
Figure 1.1: Ford model T with external sun visor [2].
Today’s sun visor is an interior solution and that was introduced to the market around 1930 [3]. The
sun visor has not been modified since then, though some alternative solutions has been designed
but never reached the market. The traditional interior sun visor is located in the roof of the car,
just above the head of the driver and passenger which is easy to reach when the surrounding light
is disturbing. An example of an interior standard sun visor in a car can be seen in Figure 1.2.
Figure 1.2: Typical design of a sun visor.
1.2 ÅF Industry AB
ÅF was founded 1845 in Malmö, Sweden and was given the name "The Southern Swedish Steam Generator Association". The main tasks was to perform frequent checks on the safety of steam generators to prevent industrial accidents [4]. ÅF is now a world leading engineering and design company within the fields of energy, industry and infrastructure. They are specialized in areas such as buildings, automotive development and renewable energy. Today, ÅF has 10 000 employees and are based in Europe and their business and clients are found all over the world [5].
The master thesis will be carried out at the research and development department (R&D) at ÅF Industry AB in Trollhättan.
1.3 Objective and purpose
The objective of this project is to create new concepts for a sun visor in a car using product development methods.
The report should include following deliverables:
• Trends and features in future cockpit referring to the sun visor as system component.
• Final proposal(s) of next generation sun visor created in CAD including its hardware such as functions and typical sections.
• Results and analysis of the outcome as well as ideas on future actions.
The purpose of this project is to design new solutions for the sun visor that has to prevent the driver and passengers from being blinded by the sunlight.
1.4 Delimitations
This project will be performed by one student for 20 weeks, 40 hours per week, as a master thesis,
30hp. This report will include the product development of the sun visor which covers analysis of
the current design, product specification, concept generation and layout engineering.
The sun visor will be restricted by following aspects:
• The design of the sun visor will be restricted by legal requirements regarding the sun visor, the windshield and the line of sight of the driver.
• No tests will be conducted on the final design of the sun visor.
• The working area of the sun visor will be restricted by the interface of the cockpit, so no adjustment of the surrounding interior will be made.
1.5 Product Development
Today, product development is a well established scientific tool when developing new products, but until 1960s, product development was more based on experience and common habit. A turning point regarding product development was when the Japanese industry became a competitor on the world leading market. Japan surpassed its competitors since they worked more systematic with clearly defined development processes and methods. They were highly focused on the products value for the customer with methods satisfying these parameters in the early phases in the development process [6].
The product development process involves synthesis and analysis aspects. Synthesis implicates new technological solutions based on functional requirements. By combining well known scientific technologies, already existing components, experience etc, new technological solutions can be fulfilled. Analysis on the other hand, implicates usage of methods, for example calculations and simulations, to investigate characteristic behaviour of an already existing system [6].
To solve a problem there is a need for a solving process in different steps where synthesis and analysis aspects are connected. These three steps are listed below:
• The process is initiated by identifying and describing the need.
• The process is continued by creating and describing possible alternatives as solutions.
• These solutions are analyzed and evaluated in regard of the needs.
The solution that fulfills all the requirements will be the final alternative. If no solution is found to
the problem, the process continuous with a new synthesis of alternatives which are analyzed and
evaluated until an acceptable solution is found. This can be described as a synthesis-analysis-loop
which requires methods that supports all three phases, requirement specification, synthesis and
analysis. By implementing these methods, a higher effectiveness will be reached which enables
development of products with high quality in perspective to the customer and a contribution to
competitiveness among the developing and producing company [6].
2 Analysis of current design
The second chapter gives an overview of the standard sun visor. Functional contents of the sun visor and all of the major components are described. Problems that can occur during use of the sun visor are formulated.
2.1 Functional content
The model name and type of the standard sun visor in Figure 2.1, and the name of the manufacturing company that owns the design rights is confidential, and the discussion limited to a functional description.
The standard sun visor is positioned in the roof just above the head of the driver and passenger.
The sun visor was disassembled from the car and can be seen in Figure 2.1. The sun visor is included with a illuminated vanity mirror which lights up when the lid is opened. The light from the lamps is useful when there is limited sunlight and the user wants to look themselves in the mirror.
Figure 2.1: The standard sun visor with closed and open lid.
Beside giving protection to the sun light, the sun visor can be seen as a contributing detail to interior class and comfort to the driver and passengers. Using the sun visor is easily done by a one hand operation.
An illustration of the sun visor when its included in the car and the shade that it gives in perspective
to forward direction can be seen in Figure 2.2.
Figure 2.2: Illustration of the sun visor and the shade it provides.
The following sequences by the sun visor can be accomplished. Through a downward motion the sun visor is folded down, see Figure 2.3.
Figure 2.3: The motion required to fold down the sun visor.
By turning the sun visor left or right, depending on the current situation in the car, the sun visor is regulated to withstand sun light from the side window, see Figure 2.4.
Figure 2.4: The motion that is needed to turn the sun visor towards the side window.
2.2 Components
To understand the concept of the standard sun visor in detail, a disassemble in the CAD model was performed. The sun visor consists of following major parts:
1. Body
2. Fixing points 3. Hinge
4. Frame 5. Sub frame 6. Vanity pack
All of the components can be seen in Figure 2.5 with its corresponding number from the list above.
Figure 2.5: An exploded view of the different parts in the sun visor.
An overview of the parts that are hidden inside the body and how they are integrated with each other can be seen in Figure 2.6.
Figure 2.6: Integration and connections of parts that are hidden inside the body.
2.2.1 Body
The body is the part that blocks the incoming light and covers the inner components of the sun visor. The material of the body is a type of thermoplastic, namely polypropylene (PP).
2.2.2 Fixing points
The fixing points controls the position of the sun visor. The components that are attached from the roof are linked to the fixing points so it is important that the fixing points are in the right position for optimal function for the sun visor. The fixing points are also made of a thermoplastic.
2.2.3 Hinge
By help of the hinge, the sun visor is able to be folded down and be moved up again to the original position. The material of the hinge is unknown.
2.2.4 Frame
The frame is the carrying structure of the sun visor and it is integrated with all other components.
It is important that the frame is robust enough to carry the body and the other components and also withstand the forces that are applied to the sun visor. The material of the frame is unknown.
2.2.5 Sub frame
The sub frame controls the stability of the mirror which needs to be stiff so that the mirror isn’t displaced. The material of the sub frame is also unknown.
2.2.6 Vanity pack
The vanity pack consist of a mirror and two lamps which are located to the sides of the mirror, see Figure 2.1. The vanity pack is integrated in the body of the sun visor.
2.3 Problem identification
Common practice for forward vision is that the height of the sun visors lower edge when it is folded down vertically (in respect to V1 point) should be about 0-2
◦, see Figure 2.7.
Figure 2.7: Height of sun visor with respect to point V1.
The point V1 is a set point where the average height and position of the eyes is located. It is determined by measuring the position of the eyes of various test persons which are all of different length and sizes. The sun visor is then regulated by this set point.
The current height and position of the sun visor causes complications for the driver and passengers.
A variation in height of the driver and passengers which deviates from point V1 implicates that the sun visor will not fulfill its purpose. The sunlight will not be blocked by the sun visor at all if a person is shorter than point V1.
The sun visor is currently fixed to one position at a time, either to the front windshield or to the side window. It might occur situations when the sun visor is needed in both positions at the same time which the standard sun visor cant satisfy.
The sun visor is currently protecting the driver from the major part of the sunlight. If the sun is setting in a certain angle in perspective to the driver, the light will reach the driver from the outer sides of the sun visor even though the sun visor is folded down.
If the sun sets low, the sun visor won’t protect the driver at all due to the limited height of the sun
visor even if the height of the driver is according to point V1.
3 Method
The following chapter describes all the methods that was used to develop the new sun visor.
3.1 Identification of customer needs
Stakeholders, in context of product development, are all that in some way will be affected or have any comments on the product and its properties during its lifecycle. The stakeholders could be individuals, groups or whole departments inside or outside the company. Requirements and requests from all the stakeholders are collected and considered when establishing the requirement specification [6]. Interviews, field visits to CEVT, China Euro Vehicle Technology AB, and research on the internet was made to identify the requirements and the requests of the stakeholders. The questionnaire that was used during the interviews can bee seen in appendix 1.
3.2 Requirement specification
The requirement specification intends to increase additional information which is missing in the description of the project assignment. A specification can be established about what is going to be accomplished, which is made in a way so that the information could be used both as a starting point for the design solutions and as a reference for the evaluation of these solutions and the final product. The requirement specification acquires high amount of information which is developed and updated continuously during the project as more knowledge about the product is gathered [6].
The requirement specification has following purpose [6]:
• To make the problem formulation more concrete
• To ensure that considerations is taken in regard for all the stakeholders, lifecycles and aspects that can affect the product
• To give all involved a clear view of the projects objective
• To make the developing process easier
• To support research of alternative solutions
• To provide a better basis to modify a requirement
The following demands is put on a requirement specification [6]:
• All the stakeholders, lifecycles and aspects must be considered
• The requirements must be formulated as independent of the solution and must be clear
• The requirements should be, if possible, measurable and controllable
• Every requirement must be unique
The requirements can be divided into two main categories. The first category involves requirements which is related to the products expected function, i.e. different functional properties and behaviors that the product is expected to possess or functional effects that the products is expected to deliver.
Examples of functional requirements in this category is "carry load", "transmit signals" and "change
direction". The other category involves requirements which limits possible solutions for the product.
Example of these requirements are "Maximum weight = 400 kg", "Need to fulfill standard XXX
" and "Need to follow legal requirement YYY". These types of requirements excludes alternative solutions that doesn’t fulfill the requirements [6].
Requirements can also be divided into demands and wishes. Demands are requirements which always must be completely fulfilled by the final product while wishes are requirements that more or less can be achieved. Therefore, the final product must completely fulfill all the demands to be an alternative product. The wishes on the other hand, can be fulfilled by the product to varying degree. Since wishes is of different importance, weight factors has been assigned to the wishes in a scale of 1-5, where 5 is of highest weight [6].
3.2.1 QFD
To connect customer needs with design requirements the Quality function deployment (QFD) method, is applied in the form of the house of quality matrix [6], see Figure 3.1.
Figure 3.1: Example of a traditional QFD-matrix [6].
The background of the term is the interpretation of the concept "quality" which is the QFD methods
starting point, namely that a products quality is defined by the costumers experience of the product.
The QFD method works as a support for the requirement specification and it is primarily the stakeholder "customer" requirements that is considered. However, the same technique can be used to consider other stakeholders requirements which is combined in the same matrix together with the stakeholder "customers" requirements [6].
The central part in Figure 3.1, is the relationship matrix and is of outmost importance. The stakeholders requirements are identified and compiled to the matrix with their respective weight to the left region of the matrix called "Customer Requirements". These customer needs is expressed as wishes, demands, and answers to what the customer wants. Thereafter, it is important to identify the requirements which can be satisfied and affected by the upcoming design solutions for the product. These design parameters answer to how the customer needs are fulfilled and are compiled to the matrix in the "measurable responses" region [6].
An assessment is based on how strongly the customer needs are connected to the product requirements and the results is inserted to the matrix, following the rating scale:
• 9 = Very strongly connected
• 3 = Moderately connected
• 1 = Weak connection
• 0 = No connection
The matrix values in the "Relationship Matrix", i.e. the connection ratings, is multiplied with the weight factors for the customer requirements and the weighted sum is calculated for every design parameter. This gives extended perception of which design parameters with corresponding demands is most important to meet the needs of the market [6].
It is relevant to identify connection between design parameters, how strongly design parameters interact with each other and if the interdependence is positive or negative. The "roof" of the QFD-matrix consists of diagonals from the various design parameters. The intersection of two different design parameters is marked depending on if the interdependence is positive or negative with following symbols:
• + = Positive relationship
• - = Negative relationship
A positive relationship denotes that improvement in meeting one of the specifications will improve the other, they are synergistic. A negative relationship shows that improvement in meeting one specification may harm the other, a compromise may be forced [7].
3.3 Competitor analysis
Competitor analysis is a tool to create awareness of what already exists by examining existing
products and reveal opportunities to improve what already exists. Competitor analysis, or benchmarking,
is a major aspect of understanding a design problem [7]. The competitor analysis was accomplished
by field visits to CEVT, China Euro Vehicle Technology AB, and internet research.
3.4 Concept generation
In this phase, a synthesis is implemented that results in several conceptual product solutions that fulfills the requirement specifications. The workflow is based on the idea to generate as many product solutions as possible where the final product solution is selected from. By performing this procedure it is ensured that all solutions are identified and none of the best solutions are forgotten [6].
The systematic concept generation is characterized by the functional requirements that concerns the future product, and the creation on many alternative solutions to fulfill these, and a systematic search for solutions is performed by:
1. Formulate the problem in a more broader, abstract and neutral form
2. Implement a functional analysis with division of the product functions in sub functions 3. Search for solutions to the sub functions
4. Combine sub solutions to complete solutions for the entire product 5. Sort out acceptable candidates
3.4.1 Formulation of the problem
The purpose of formulating the problem in a broader, abstract and neutral form is to find general solutions to the problem. This implies that a new formulation regarding the concrete and detailed descriptions for the functional requirements in the requirement specification, which results as a basis for the upcoming functional analysis [6].
3.4.2 Functional analysis
The purpose of the functional analysis is to create a functional structure which visualizes all the functions which the product and all the included parts need to perform. The result is a functional structure where the products complex total function is realized of the cooperating included sub functions. The purpose of this procedure is to divide the overall problem into several sub problems and find solutions that fulfills every sub function. This is easier than finding a total solution that solves the total complex problem [6].
3.4.3 Creative methods
Identification of solutions for the sub functions in the functional structure is made systematically and methodically. It is of utmost importance to generate ideas that can lead to insight, and to successive improve these ideas until there are a practical viable solution to the problem. A creative way to generate ideas and to find solutions is by brainstorming [6].
Brainstorming is performed in a group where the main task is to achieve as many ideas as possible.
The amount of ideas is prioritized before the quality of the ideas. The group participants should
inspire each other to produce new ideas through associations to other people’s ideas in the group [6].
There are four basic rules to take into account when brainstorming:
1. Criticism is not allowed 2. Quantity is sought for 3. Go outside the box 4. Combine ideas
Two different groups were formed for the brainstorming session. One group with employed engineers from ÅF within different working areas. The participants were of different gender, height and age. Seven participants were in this group. The participants from the other group were of other professions with different gender, height and age and a total of six persons were in this group.
The different sub solutions that has been generated to achieve the identified demands for the sub functions is combined to a complete solution for the entire product. The aim is a number of complete solutions which all fulfills the requirements in the requirement specification. A morphological matrix is used for this purpose, see Figure 3.2.
Figure 3.2: An example of how to combine solutions in a morphological matrix [6].
Alternatives that doesn’t satisfy all the requirements or isn’t geometrical or physical compatible or by some other reasons isn’t reasonable is sorted out.
3.5 Concept selection
The evaluation of alternative solutions that is generated in the concept generation implies that every alternative should be analyzed with the intention of determining its value and quality relative to the demands and wishes that was formulated in the requirement specification. The task is then to compare the results from the analysis and make a decision about which alternative has highest value and quality [6].
The concept selection process is implemented in following steps:
1. Concept screening with an elimination matrix
2. Concept scoring with a weighted relative decision matrix
In the process, the concepts that passes a decision phase are further developed [6], see Figure 3.3.
Figure 3.3: The evaluation of concepts according to Ulrich and Eppinger [6].
3.5.1 Concept screening
The first step in the concept selection process is to eliminate less effective concepts. This phase has already begun during the completion of the concept generation phase where a first sorting of unreasonable concepts are performed. The existing concepts are now evaluated in regard to:
• Solving the main problem
• Fulfills all the requirements
• Realizable
• Within the cost range
• Secure and ergonomic
• Suits the company
• Sufficient information
The concepts that entirely fulfills these requirements in addition to the concepts that needs further
evaluation proceeds in the process. To support this first evaluation of concepts, an elimination
matrix is used, see table 3.1.
Table 3.1: Elimination matrix after Pahl and Beitz [6]
The concepts that has been decided to proceed with (+) goes directly to the next evaluation phase. The concepts that needs more information (?) is evaluated in regard to continuation (+) or elimination (-) until a decision can be made [6].
3.5.2 Concept scoring
The next step in the concept selection process is evaluation by a weighted relative decision matrix.
By using this method, the amounts of concepts is further reduced by sorting out the worst concepts.
However, it can occur that new solutions are found through combinations of previous concepts.
These new solutions are added to the total amount of concepts [6].
In a weighted relative decision matrix, the selection is based on relative comparisons between different concepts. Following aspects are important to take into account:
• The requirements are based on the requirement specifications wishes and demands.
• Cover all the relevant aspects, but with focus on the problem that the product actually needs to solve.
• A maximum of 15-20 requirements are formulated.
• Merge detailed requirements into groups if necessary.
The selection and evaluation of concepts are then performed with the weighted relative decision
matrix, see table 3.2.
Table 3.2: Weighted relative decision matrix according to Pugh [6]
The requirements and the concepts are then added into the matrix. A reference concept (DATUM) is also added into the matrix. The reference concept can for example be an already existing concept.
All the concepts are now compared to the reference concept. It is now decided, for each of the requirements, whether or not the current concept fulfills the current requirement better than (+), as good as (0) or worse than (-) the reference concept. The result of the comparison (+,0 or -) is added into the current box in the matrix. When all of the requirements and concepts has been processed, every concepts assessment (+,0 or -) are summed up and multiplied with the corresponding weight of the current requirement. The assessments that has been summarized acts as a starting point for the net value that is calculated for every concept which is then ranked based on the obtained net value. Decisions are then made about which concepts to proceed with based on the ranking and the relationship between the net values [6].
Before the next evaluation round, it should also be examined if new, more compatible concepts than the existing can be created through
• Modification of already existing concepts so that their minus evaluation is eliminated.
• Combination of concepts with different strengths so that the combined proposal gets considered positive assessments.
3.6 Product design
The chosen concept was further developed to a functioning product that fulfilled the requirements in the requirement specification. The objective in this phase was to create a basis that described a functioning and usable product. The design and configuration of the product is made by:
• Dimension and selecting standard components
• Design new, unique components
• Define the products structure
• Describe the products layout
The final design was made by CAD with help of the software CATIA V5.
3.7 Material selection
The method used to select materials for the sun visor was made with internet research, CES Edupack [8] and with the strategy according to [9], see Figure 3.4.
Figure 3.4: Method to select materials [9].
3.7.1 Translate design requirements
In the translation phase, the component is described with functions, constraints, objectives and free variables. The term function is describing what the component is supposed to do, e.g. support a load or contain heat. The term constraints defines which properties that are fixed, e.g. dimensions.
An objective is always aimed at when designing a component, e.g. to make it cheaper or to minimize the weight which is the third term in this phase. The final term free variables categorizes which properties that are flexible, e.g. free dimensions or choice of material. These four terms defines the boundary conditions of the choice of material. They are answering to different questions when selecting a material [9]:
• Function - What does the component do?
• Constraints - What nonnegotiable conditions must be met? What negotiable but desirable
conditions must be met?
• Objective - What is to be maximized or minimized?
• Free variable - Which parameters of the problem is the designer free to change?
3.7.2 Screen using constraints
All materials are considered as candidates to begin with. Screening eliminates material candidates that cannot fulfill the constraints set in the translation phase [9].
3.7.3 Rank using objective
The materials that are left after the screening are ranked with help of material indices, which measures how well a candidate that has passed the screening can perform. Performance is sometimes limited by a single property or a combination of properties. For example, the best property for buoyancy is a low density and the best property for a heat exchanger is a high thermal conductivity.
So by minimizing or maximizing a single property is maximizing performance. The property or properties that are maximizing performance is called material index and following sequence is made for finding a material index [9].
First, the function, constraints, objective and free variables needs to be defined. Secondly, an equation is needed that is describing the quantity to be maximized or minimized, called an objective function, and an equation for the constraints are needed. Thereafter, substituting the equation for the constraints into the objective function gives equation 3.1
P = f (F, G, M ) (3.1)
Here stands F for functional requirement, G stand for geometric parameters and M stands for material properties which is the material index. The material index is then inserted into CES Edupack to obtain possible material candidates [9].
3.7.4 Seek documentation
After the material index is inserted into CES Edupack, a ranked list is obtained with the best material candidates. The next step is to seek documentation about the top listed candidates to found out more about the materials and to pick one that suits the design best. Information about the materials are often found in handbooks, suppliers data sheets, case studies and failure analyses [9].
3.8 Future trends of sun visors
Future trends of sun visors was examined by internet research.
4 Results
This chapter represents all of the produced results, including identification of costumers needs, requirement specification, competitor analysis, concept generation and selection, product design and material selection.
4.1 Identification of customer needs
The identified stakeholders and their input and output towards the project and the sun visor can be seen in table 4.1.
Table 4.1: Identification of customer needs
Stakeholder Input Output
ÅF Knowledge and product requirements New product Marketing Customer needs and wishes New product to use
Competitors Inspiration Competition on the market Society Legal requirements Safe products
Standards Regulations and limitations Safe products
4.2 Requirement specification
Following requirement specification was produced. Wishes and demands are marked with "W" and
"D" for each requirement.
1. Legal requirements
The sun visor must follow regulation ECE 21 paragraph 5.3.4.1 regarding components mounted on the roof, width of projecting parts and downward projection. See annex 10 paragraph 5.3.4.1 for explanatory notes. Alternatively, these projecting parts shall pass
the energy-dissipating test according to annex 4 [10]. D
The sun visor must follow regulation ECE 21 paragraph 5.4.2.3 regarding metal wires attached to the sun visor and non-rigid attachment elements of the frames of the
sun visor [10]. D
Regulation ECE No.94 paragraph 1.4.3.7 must be followed regarding the sun visors
position [11]. D
The sun visor must follow regulation ECE No.94 paragraph 6.2.2 regarding frontal
protection airbag and warning labels [11]. D
Regulation EEC 77/649 paragraph 2.12 must be followed regarding transparent area of
the windshield [12]. D
Regulation EEC 77/649 paragraph 5.1.1 - 5.1.1.4 must be fulfilled regarding drivers
field of vision and transparent area of the windshield [12]. D
Regulation TSFS 2013:63, chapter 31, paragraph 5 must be followed regarding colored
films and reflection of the windshield [13]. D
Regulation EEC 77/649 paragraph 5.1.3 must be followed regarding obstructions in
the drivers 180
◦forward direct field of vision [12]. D
2. Functions
The function of the sun visor shall work for the windshield and the side window. D
The sun visor should block the incoming sunlight from the windshield and the side
window at the same time. W
The sun visor shall be able to block the sunlight regardless of the suns position.
For instance leakage between the sun visor and the rear mirror. W The sun visor shall be able to block the sunlight regardless of the
position of the drivers head. W
The sun visor shall be easy to operate so the driving isn’t affected negatively. D The sun visor shall block incoming light regardless of source. W Light from headlights from oncoming cars in the night shall be blocked. W
Low time to function. W
3. Design
Contain vanity pack W
Contain a ticket holder. W
The design should implement an interior class and comfort to the driver and passenger. W The design of the sun visor shall not change the design of the surrounding interior. D
The sun visor should be user friendly. W
Free from noise. D
Symmetric design, used for both left and right side of the car. W
The sun visor should be robust. W
Polarizing effect. W
4. General
Low weight. W
Few parts. W
Recyclable material. W
4.2.1 QFD
The final QFD matrix can be seen in Appendix 2. By looking at the weighted ranking, it should be emphasized that blocking incoming light for the windshield and the side window at the same time and block incoming light regardless of source is of highest importance. Following functional requirements should also be prioritized: the sun visor should work for the windshield and the side window, the sun visor should be able to block the sunlight regardless of the suns position and the sun visor shall be able to block the sunlight regardless of the position of the drivers head. It should be highlighted that all of the highest ranked functional requirements concerns blockage of incoming light.
4.3 Competitor analysis
Four different competitors was analyzed and following results of the competitor analysis was conducted. Also, a final evaluation of all the competitors can be seen in appendix 3, table A.3.
4.3.1 Volvo V60
One competitor that was analyzed was the sun visor of a Volvo V60, see Figure 4.1.
Figure 4.1: The sun visor with closed and open lid.
This sun visor is mounted in the roof and has approximately the same size and shape as the standard sun visor. The sun visor is also able to block incoming light from the windshield and the side window with the same movement pattern as for the current solution. Two details that are different are the ticket holder which Volvo V60 has and just one lamp in the vanity mirror package compared to the standard sun visor.
The sun visor was disassembled and following major components was detected:
An outer layer was detected which covers the body. The material of this component is presumed to be plastic. The outer layer can be seen in Figure 4.2.
Figure 4.2: Outer layer of the sun visor.
The body of the sun visor with and without vanity pack can be seen in Figure 4.3. The material
of the body is presumably a thermoset.
Figure 4.3: The body of the sun visor with and without the vanity pack attached.
The body was possible to split in half so the content of the body was visible, see Figure 4.4.
Figure 4.4: Half of the body.
Finally, the hinge of the current design was also found in the investigated solution which was attached to the link between the sun visor and the roof, see Figure 4.5. The material of the hinge consists of a metal.
Figure 4.5: The hinge of the sun visor.
The fixing points, the frame and the sub frame of the standard sun visor was observed to be non existing in the sun visor of Volvo V60.
4.3.2 Tesla Model X
Another competitor that was analyzed was the Tesla Model X, and they are using a panoramic
windshield which differs from the current solution, see Figure 4.6.
Figure 4.6: Panoramic windshield of a Tesla Model x. Courtesy: Edmunds.com Inc, [14].
Tesla Model X uses a tinted glass roof to be able to block out sunlight when the sun is positioned above the car. To be able to block out incoming light below the tinted glass without a roof to attach the sun visors to, Tesla uses sun visor that are attached to the A-pillars, see Figure 4.7. The different pillars of the car can be seen in appendix 4, Figure A.4.1.
Figure 4.7: The sun visor attached to the A-pillar. Courtesy: Edmunds.com Inc, [14].
The sun visors are then attached to the rear view mirror via magnets to position the sun visor in
front of the driver or the passenger, see Figure 4.8.
Figure 4.8: Position of the sun visor. Courtesy: Edmunds.com Inc, [14].
The sun visor also has the ability to be extended to block out even more incoming light which is the condition in Figure 4.8. Incoming light from the side window can be blocked out by lowering the sun visor from the position that can be seen in Figure 4.7. The Tesla Model X also has a vanity mirror inside the sun visor with two lamps (not shown in the figures). No detailed comparison of the components of the sun visors could be completed.
4.3.3 Kia Ceed
The third competitor that was analyzed was a Kia Ceed. The sun visor of the Kia Ceed can be seen in Figure 4.9. The sun visor is attached to the roof just above the head of the driver and passenger which is the same case as for the current solution. The sun visor is in a stowed position and it can be visualized that a modification of the roof has been made at the right side of the sun visor so the user has an easier time to pull down the sun visor.
Figure 4.9: The sun visor in a retracted position.
The sun visor in a vertical position can be seen in Figure 4.10. The shape and size of the sun visor
is approximately the same as the standard sun visor. A ticket holder is attached to the sun visor and the vanity mirror is opened by a sliding motion of the lid. The lamp is attached to the roof and not beside the mirror with differs from the current solution, see Figure 4.10.
Figure 4.10: The sun visor in a down folded position with visible mirror.
The same movement is used to move the sun visor to the side window as for the current product.
The sun visor of the Kia, when located at the side window, is too short to cover the whole length of the side window. Therefore, the driver needs to lean forward in certain situations to prevent from being blinded, see Figure 4.11.
Figure 4.11: The sun visors side position.
4.3.4 SAAB 9-5
The sun visor for a SAAB 9-5 was analyzed due to the special ability to prevent incoming light
at the windshield and at the side window at the same time. The sun visors are attached above
the head of the driver and passenger and the size of the both sun visors are similar to the current
product. The sun visors in a retracted position can be seen in Figure 4.12. A modification to the
roof has been made to make the sun visor user friendly. The process to fold down the sun visor is
easier.
Figure 4.12: The sun visor in a stowed position.
An option is to have only one sun visor in use at the time, for the windshield or at the side window.
The case for the windshield can be seen in Figure 4.13. The retracted position for the second sun visor is located above the first sun visor and the vanity mirror has double lamps for extra illumination, see Figure 4.13.
Figure 4.13: One sun visor in use, preventing incoming light from the windshield with vanity mirror with two lamps.
The combination of having one sun visor facing the side window and free sight at the windshield
and the option to have both sun visors in use at the same time can be seen in Figure 4.14.
Figure 4.14: Combination of different ways to adjust the sun visor.
The sun visor facing the side window is wide enough to block incoming light from the side, see Figure 4.15.
Figure 4.15: Sufficient blockage from the side.
4.4 Concept generation
Elimination of unreasonable concepts has been performed during the concept generation phase and these concepts can be seen in appendix 5. All of the remaining concepts that passed this first elimination phase are presented below.
1
Use a privacy filter for computer screens as a sun visor. Privacy filters blocks the content on the computer screen when looking from the side. The content on the computer screen is only visible when looking directly in front of the computer screen.
2
Use privacy filters for the whole windshield and side windows.
3
Figure 4.16: Fully tinted windshield and side window.
Tinted glass for the whole windshield and side window. The windshield and side windows are made of a photochromic glass [15], or electrochromic glass [16].
4
Figure 4.17: Tinted strips in the windshield.
Strips are attached in the windshield and side window that are tinted. The strips are controlled by an eye tracker and the dark spot moves by the position of the head in regard to the incoming light. The strips are made of a photochromic glass or electrochromic glass.
5
The sun visor is fully tinted with photochromic glass or electrochromic glass.
6
The windshield and side windows are made of one way or two way glass which blockades the incoming light.
7
The windshield and side windows are made of opaque glass that can be turned on and off by an electric current. Strips and eye tracker is used as in concept 4.
8
The windshield and side windows are made of colored glass that increases the visibility.
9
The windshield and side windows are polarized which makes the visibility clearer.
10
The sun visor is polarized.
11
The car turns into autonomous drive when the incoming light is too strong.
12
Coated window that blocks the light.
13
Figure 4.18: Vertical curtain.
Use curtains at the windshield and side windows that can be pulled down and up vertically by an electric motor.
14
Figure 4.19: Horizontal curtain.
Use curtains at the windshield and side windows that can be extended horizontally by an electric motor.
15
Figure 4.20: Rotating sun visor.
Rotating sun visor which can be angled to the incoming
light.
16
Figure 4.21: Extra protection against incoming light.
The sun visor is in a fixed position but extra protection can be unfolded both vertically and horizontally.
17
Figure 4.22: Sliding sun visor.
The sun visor is attached to a rail which the sun visor can slide on between the windshield and the side window.
18
Figure 4.23: Two sun visor that are attached to each other.
Double sun visors that are attached to each other so the
sun visor can block incoming light from the front and the
side at the same time. The sun visors are also able to be
extended vertically.
19
Figure 4.24: Sun visor that are maneuvered by the use of ball joints.
Ball joints are used so the sun visor is able to be rotated in all directions, both for the windshield and the side window.
20
Figure 4.25: Two separate sun visors.
Two sun visors which are located at the windshield and the side window. The sun visors are able to be extended vertically and horizontally.
4.5 Concept selection
The concepts were narrowed down further by implementing concept screening and concept scoring with an elimination matrix and a weighted relative decision matrix.
4.5.1 Concept screening
The concepts were added into the elimination matrix and was evaluated and the result can be seen
in table 4.2.
Table 4.2: Elimination matrix
No concepts directly passed the first screening due to following legal requirements. Regulation
EEC 77/649 paragraph 5.1.1 - 5.1.1.4 regarding drivers field of vision and transparent area of the
windshield and regulation EEC 77/649 paragraph 5.1.3 regarding obstructions in the drivers 180
◦forward direct field of vision [12]. The geometry of the concepts needs to fit the legal requirements
and a second concept screening was made in regard to the geometry that needs to be fulfilled for these legal requirements. The geometry that needs to be fulfilled can be seen in appendix 6. The generated concepts were adapted to fit the legal requirements and the second concept screening can be seen in table 4.3.
Table 4.3: Elimination matrix with concepts adapted to legal requirements
Concept 1 that needed more information about the privacy filter was found out during interviews at ÅF. The privacy filter concept has actually been tested as a sun visor with good results during the day but insufficient results during the night. When used at night, oncoming car lights was doubled so four light sources was visualized rather than two.
Concept 5 and 10 could be used as sun visors but must be combined with another sun visor concept.
These concepts will be continued with if a decision about a similar solution to the standard sun visor is proceeded with.
Information about coatings for concept 12 were unavailable to find to fit a solution for a sun visor.
4.5.2 Concept scoring
The concepts that passed the concept screening phase were inserted into the weighted relative decision matrix and the evaluation can be seen in table 4.4. The reference concept in the weighted relative decision matrix was the analyzed sun visor introduced in chapter 2.
Table 4.4: Evaluated weighted relative decision matrix
All the concepts that was evaluated had a better ranking than the reference concept. The top
candidates were concept 13 and 14. Only concept 13 were chosen to be continued with because of
the similar solutions and because of the increased visibility if the incoming light is higher up on the
windshield. Concept 14 needs to be extended horizontally across the windshield and the sun visor
itself blocks the line of sight. A modification of concept 13 was developed to concept 13 b and 13
c, see Figure 4.26, where the curtain is divided into two separate curtains. The curtains in concept
13 b is pulled down by an electric motor by pushing a button and 13 c is a mechanical concept where the driver or passenger manually pulls down the curtain.
Figure 4.26: Concept 13 b and 13 c, two separate curtains for the windshield.
A concept of a vertical curtain for the windshield and a horizontal curtain for the side window was also developed called 13 d and 13 e. Concept 13 d is maneuvered by an electric motor and 13 e is maneuvered manually.
Figure 4.27: Concept 13 d and 13 e.
Concept 18 was modified into concept 18 b, see Figure 4.28, where the sun visors are able to be extended horizontally.
Figure 4.28: Concept 18 b.
No modifications was found for concept 3, 4, 7 and 20 but they were all passed on to the fourth selection.
Concept 13 had the highest net value in the first selection which made the modified concept 13 b
a good candidate as a reference concept in the fourth selection, see table 4.5.
Table 4.5: The second weighted relative decision matrix
Concept 13 b and 13 d were the superior candidates. However, 13 d was easier to implement in the front door due to more space in the side frame of the door. Concept 13 b had a limited space and a decision was made to move forward with concept 13 d for further development. In comparison to the standard sun visor, the curtain solution covers more of the windshield and side window which provides better blockage for incoming light. Also, the leakage between the sun visor and the rear mirror is eliminated. If the light is located from the passenger side, there is an option for the driver to extend the sun visor horizontally which is not available in the current solution.
Furthermore, the design of the new sun visor was adapted to a car with a WEM cover as a feature.
The chosen concept was modified to fit the WEM covers design but the concept itself was the same.
The WEM cover was not taken into account during the concept generation phase due to a risk of
limited concepts. A typical WEM cover can be seen in Figure 4.29.
Figure 4.29: WEM cover with rear view mirror attached.
4.6 Product design
The new sun visor in a front view can be seen in Figure 4.30, and rear view in Figure 4.31, where the sun curtain is folded out along the windshield. The new sun visor does not fit in the current car due to limited space but is designed as closely as possible to the available space. The sun visor for the side window was not designed in CAD due to limited time and is left for future work.
Figure 4.30: Final design of the sun visor for the windshield.
Figure 4.31: Rear view of the sun visor.
The curtain is attached to a shaft which it is rolled up by a motor, see Figure 4.32. The shaft is stabilized with housings which are screwed to the inner roof. Plain bearings are assembled between the shaft and the housing to make an easier rotating motion for the curtain when it is rolled up and down. Circlips are stabilizing the shaft so no axial movement is available. A motor is attached to the shaft but the exact size and type of motor is not decided and is left for future work.
Figure 4.32: The left shaft that the curtain is attached on and the rear mirror can be seen.
The curtain is rolled down through a gap in the roof and is guided in the right direction by snap
hooks, see Figure 4.33.
Figure 4.33: Side view of the sun visor.
The lower part of the curtain is attached to a shaft with wheels and the wheels are rolling in a profile located in the a-pillars and the WEM cover, see Figure 4.34.
Figure 4.34: Profiles in the WEM cover where the wheels are located.
Extension springs are attached to the a-pillar, WEM cover and to the wheel shaft, see Figure
4.35-4.36. The extension springs are pulling the curtain down due to the tension in the springs
and the motor are controlling the upward motion. By stopping the motor, the curtain is set to a
specific height.
Figure 4.35: Spring attached to the wheel shaft for the A-pillar.
Figure 4.36: Spring attached to the wheel shaft for the WEM cover.
The length of the springs needs to be exactly as long as the height of the curtain that goes down to point V
1to be able to cover the incoming light. The springs can be extracted to the inner roof but they can’t be compressed to the bottom of the A-pillar or to the WEM cover. The springs has a bottom position and they can’t be compressed below that point. The profile in the A-pillar can be elongated so the spring can reach the length of point V
1and to the inner roof but the WEM cover can’t be elongated below point V
1. This problem leads to that the curtain can’t go down fully to point V
1and all the incoming light won’t be blocked.
4.6.1 Shaft
The shaft is the component where the curtain is rolled up to by a motor and can be seen in Figure
4.37.
Figure 4.37: Shaft for the sun curtain.
The shaft has a profile where the end of the curtain is attached in with the same width as the sun curtain. Two profiles is located near the end of the shaft where circlips is assembled against the plain bearings which makes the shaft more stabilized. One end of the shaft has an opening for the shaft from the motor which fits between the motor shaft and the curtain shaft.
4.6.2 Housing
The housing of the shaft can be seen in Figure 4.38. The inner diameter is bigger than the shaft
due to make space for a plain bearing that is attached between the shaft and the housing for easier
sliding. The housing is screwed to the inner roof of the car.
Figure 4.38: Housing for the curtain shaft.
4.6.3 Curtain
The curtain has the width according to the length between the a-pillar and the WEM cover to be able to block incoming light to the car as much as possible. The length of the curtain is limited to point V
1and to the shaft that connects with the curtain. The curtain has a bit of transparency which makes it possible for the driver to see contours in the drivers field of vision but still blocks the incoming light.
4.6.4 A-pillar
A simplified a-pillar was made in CAD, see Figure 4.39. A profile can be seen where the curtain is
rolling up and down. The length of the profiles enables the sun curtain to go down to point V
1.
Figure 4.39: The outside and inside of the a-pillar.
Ribs are attached to the profiles to make them more stable, see Figure 4.40.
Figure 4.40: Profile with ribs.
4.6.5 WEM
A simplified WEM cover was made in CAD with exact same profiles and ribs as for the A-pillar,
see Figure 4.41. The WEM cover is larger than its precursor due to that the sun curtain is going
down to the V
1point so the WEM cover needs to be elongated. There are no legal requirements that says that the WEM cover can’t go down to that point.
Figure 4.41: Simplified WEM cover with profiles and ribs.
4.6.6 Roof
The inner roof of the car can be seen in Figure 4.42 where gaps for the curtain to pass through can
be seen and screw holes for the housing.
Figure 4.42: Inner roof of the car.
4.6.7 Snap hook
The snap hooks stabilizes the component so the rail can guide the curtain to the right path, see Figure 4.43. The snap hook is resilient which makes it easy to assemble into the roof. The snap hooks has been designed in regard to the guidelines that ÅF uses, see appendix 7.
Figure 4.43: Snap hooks and rail for the sun curtain.
4.6.8 Wheel shaft
The shaft for the wheels and lower part for the curtain which stabilizes the curtain can be seen in
Figure 4.44. The curtain encircles the middle part of the shaft and the ends of the shaft is attached
to the wheels that rolls in the profiles of the a-pillars and the WEM cover.
Figure 4.44: Shaft for the wheels and sun curtain.
