1985-89 toyota mr2 power steering - uc drc home

1985-89 TOYOTA MR2 POWER STEERING

A Baccalaureate thesis submitted to the School of Dynamic Systems

College of Engineering and Applied Science University of Cincinnati

in partial fulfillment of the

requirements for the degree of

Bachelor of Science

in Mechanical Engineering Technology

by

Adam Close

April 2013

Thesis Advisor: Dr. Janak Dave

i

TABLE OF CONTENTS

TABLE OF CONTENTS ........................................................................................................... I

LIST OF FIGURES .................................................................................................................. II

LIST OF TABLES .................................................................................................................. III

ABSTRACT ............................................................................................................................ IV

INTRODUCTION AND RESEARCH ..................................................................................... 1

PROBLEM STATEMENT ........................................................................................................................................ 1 INTERVIEWS ........................................................................................................................................................ 2 HYDRAULIC POWER STEERING ........................................................................................................................... 3 FLAMING RIVER POWER STEERING RACK WITH TILT COLUMN ......................................................................... 4 ELECTRO-HYDRAULIC POWER STEERING ........................................................................................................... 5 MK2 POWERED MK1 MR2 .................................................................................................................................... 5 ELECTRIC POWER STEERING .............................................................................................................................. 6 UNIVERSAL ELECTRA-STEER ............................................................................................................................. 7 ADJUSTABLE POWER STEERING ......................................................................................................................... 8 STEER-BY-WIRE .................................................................................................................................................. 9

CUSTOMER FEEDBACK, FEATURES AND OBJECTIVES ............................................ 10

SURVEY ANALYSIS ............................................................................................................................................ 10 PRODUCT FEATURES AND OBJECTIVES .............................................................................................................. 11 ENGINEERING CHARACTERISTICS ...................................................................................................................... 12

DESIGN ALTERNATIVES AND SELECTION .................................................................. 13

LOADING CONDITIONS CALCULATIONS ..................................................................... 14

COMPONENT AND MATERIAL SELECTION.................................................................. 17

FABRICATION AND ASSEMBLY ...................................................................................... 20

TESTING AND PROOF OF DESIGN .................................................................................. 25

SCHEDULE AND BUDGET ................................................................................................. 26

SCHEDULE ........................................................................................................................................................ 26 BUDGET ............................................................................................................................................................ 27

RECOMMENDATIONS ........................................................................................................ 28

WORKS CITED ..................................................................................................................... 29

APPENDIX A - RESEARCH ................................................................................................... 1

APPENDIX B - SURVEY ........................................................................................................ 1

APPENDIX C – PRODUCT OBJECTIVES ............................................................................ 1

APPENDIX D – QUALITY FUNCTION DEPLOYMENT .................................................... 1

APPENDIX E – CALCULATIONS ......................................................................................... 1

APPENDIX F – SCHEDULE ................................................................................................... 1

ii

APPENDIX G - BUDGET ....................................................................................................... 1

APPENDIX H – DRAWINGS ................................................................................................. 1

APPENDIX I – PRESENTATION ........................................................................................... 1

APPENDIX J – WIRING DIAGRAM ..................................................................................... 1

APPENDIX K – WIRE ROUTING .......................................................................................... 1

LIST OF FIGURES Figure 1 - Hydraulic Power Steering ........................................................................................ 3

Figure 2 - Flaming River Mustang Kit ..................................................................................... 4

Figure 3 - Electro-Hydraulic Power Steering ........................................................................... 5

Figure 4 - Electric Power Steering ............................................................................................ 6

Figure 5 – Universal Electra Steer ............................................................................................ 7

Figure 6 - Before Installation .................................................................................................... 8

Figure 7 - After Installation ...................................................................................................... 8

Figure 8 – Steer-By-Wire .......................................................................................................... 9

Figure 9 – Column Design ...................................................................................................... 13

Figure 10 – Steering Effort ..................................................................................................... 14

Figure 11 – Solid Model Assembly ........................................................................................ 14

Figure 12 – Exploded Stress Area .......................................................................................... 14

Figure 13 – Stress Concentration Factor Graph ...................................................................... 15

Figure 14 - Easysteer .............................................................................................................. 17

Figure 15 – Coupler ................................................................................................................ 18

Figure 16 – Rod ...................................................................................................................... 19

Figure 17 – Tube ..................................................................................................................... 19

Figure 18 – Stock Column Disassembled ............................................................................... 20

Figure 19 – Cutting the Stock Column ................................................................................... 20

Figure 20 – Cut Upper Shaft ................................................................................................... 20

Figure 21 – Splined Shaft ....................................................................................................... 21

Figure 22 – Upper Shaft Assembly ......................................................................................... 21

Figure 23 – Lower Shaft Components .................................................................................... 21

Figure 24 – Lower Shaft Assembly ........................................................................................ 22

Figure 25 – Alignment Marks ................................................................................................. 22

Figure 26 – Upper and Lower Body Alignment ..................................................................... 23

Figure 27 – Power Steering Column Disassembled ............................................................... 23

Figure 28 – Power Steering Column Assembled .................................................................... 23

Figure 29 – Knob Location ..................................................................................................... 24

Figure 30 – Power Steering Column Installed ........................................................................ 24

Figure 31 – Effort of 7 lbs....................................................................................................... 25

iii

LIST OF TABLES Table 1 – Survey Results 10

Table 2 – Engineering Characteristics 12

Table 3 – Design Evaluations 13

Table 4 – Stress Analysis 16

Table 5 – Spring Pins 18

Table 6 – Schedule 26

Table 7 – Budget 27

iv

ABSTRACT The 1985-89 Toyota MR2 is lighter than most cars but can still benefit greatly with the

use of power steering. Currently, there are no power steering kits for the MR2. One person

managed to incorporate power steering into his MR2 in two different ways. His first attempt

had poor results and the second attempt was successful but did not reveal much information

about it.

By exploring the different types of power steering and conducting interviews, product

features are developed and put into a survey that are voted on by importance. These features

are then put into measurable goals called Objectives. From there, three types of power

steering designs are rated based on their performance in with the Objectives. The result is an

Electric Power Steering System that reduces the driver’s steering effort by as much as 62%

and bolts directly in place of the old MR2 column with minor modifications around the dash

area. The design takes the original column’s one piece body and one piece shaft and cuts out

the middle sections of both and integrates an electric motor in their place.

1985-89 MR2 POWER STEERING ADAM CLOSE

1

INTRODUCTION AND RESEARCH

PROBLEM STATEMENT The 1985-89 Toyota MR2 is a mid-engine, rear-wheel-drive, two-seater. It is a great

commuter car because it gets up to 32 highway miles per gallon and fits into tight parking

spaces. The only problem is it never came with power steering which makes parking a bit

more of a hassle and sometimes dangerous. One example that shows this is parallel parking

on a busy city street. It must be done quickly and accurately. Without power steering, the

driver must use the strength of both hands and the mirrors without the ability to turn around

and look directly where he or she is going like most driver’s like to do. This takes a little

more time and possibly a few tries which is dangerous in heavy traffic. Although the MR2 is

lighter than most cars it is still heavy enough to benefit from power steering.

A power steering kit for the MR2 will give the driver the ability to turn the steering wheel

with the palm of one hand and make it safely into a parking spot.


2

INTERVIEWS Interviews with daily commuters are conducted to find what features are enjoyed most.

In an interview with Paula Walker, it is found that she use to drive a 1956 Buick Special

that had a semi truck size steering wheel and no power steering. She feels that non-power

steering is not difficult on city streets except when parallel parking. Paula says vehicles with

power steering are much easier to drive all-around and prefers a modern size steering wheel

with power steering. (1)

Jen Walker drives a 2004 Infinity G35 and likes how responsive the steering is. (2)

Joyce Close remembers driving a 1995 Ford Van and a 2000 Ford 350 Truck in which

both power steering systems developed play. Her only desire is for a reliable power steering

system. (3)

Dan Close is not only a daily commuter but also a novice racecar driver. His only care

for his daily driver is that it has low steering effort. As for his racecar, he needs to have

responsive steering. (4)

After getting to know what commuters think about their power steering features, power

steering systems are explored to find advantages and disadvantages.


3

HYDRAULIC POWER STEERING There are four types of power steering that use a rack and pinion. They are Hydraulic

Power Steering (HPS), Electro-Hydraulic Power Steering (EHPS), Electric Power Steering

(EPS) and Steer-By-Wire.

In Hydraulic Power Steering, a pulley driven pump mounted on the engine forces

hydraulic fluid through a control valve on the steering column and into the power steering

rack on both sides of a piston as shown in Figure 1 (5). When the steering wheel is turning, a

thin torsion bar inside the control valve is being twisted letting more fluid into one side of the

piston and forcing it to help turn the wheels proportional to the amount of torque being

applied to the steering wheel. An advantage of HPS over EHPS and EPS is that it doesn’t use

electronics making it easier to work on for the Do-It-Yourself (DIY) person. The

disadvantages are leaking hydraulic fluid, routine maintenance, and needing to run hydraulic

lines from the rack to the pump on the engine. Also, because the HPS pump is driven by the

engine, it decreases horsepower, fuel economy and the pump’s life because it is running all

the time.

Figure 1 - Hydraulic Power Steering

HPS is still the most common type in today’s vehicles. Less common vehicle designs

will be discussed later for using other power steering systems. One aftermarket company that

sells HPS kits for vehicles without power steering is Flaming River.


4

FLAMING RIVER POWER STEERING RACK WITH TILT COLUMN Flaming River is a company that makes steering components like power steering racks

for domestic muscle cars that didn’t come with them from the factory. Among them is a

power steering kit for the 1965-70 Ford Mustang shown in Figure 2 (6). The company

claims, “They feature a cradle that mounts in the original chassis location with no

modification, and the center support does not have to be removed. The kits include: a new tilt

steering column with universal joints, shafting, support bearing, billet aluminum reservoir,

power rack and pinion, and mounting cradle. They also include all grade 8 mounting

hardware and a variable pressure pump for true-steering driving performance.”

Figure 2 - Flaming River Mustang Kit

The next type of system is Electro-Hydraulic Power Steering.


5

ELECTRO-HYDRAULIC POWER STEERING Electro-Hydraulic Power Steering works the same as HPS except that it uses an electric

motor to drive the pump instead of the engine and pulley. Along with the control valve the

EHPS also uses a computer that takes the vehicles speed into consideration and adjusts the

amount of force used to help turn the wheels. The advantages of EHPS are being able to

place the motor and pump anywhere, increased pump life and does not reduce horsepower

and fuel economy. The disadvantages are it still leaks fluid and requires routine maintenance.

Figure 3 (7) shows a diagram of the EHPS.

Figure 3 - Electro-Hydraulic Power Steering

Car manufactures typically use EHPS when the engine is in the rear of the vehicle. This

eliminates installing lengthy and complex shaped hydraulic lines. No aftermarket kits are

available but some people integrate systems from vehicles that came with them into their

own vehicle. One example is Paul Woods and his MK2 powered MK1 MR2.

MK2 POWERED MK1 MR2 In the Adjustable Power Steering discussion on www.imoc.co.uk that will be mentioned

more later, Paul Woods mentions, “A few years ago I retro fitted a Mk2 PAS system onto a

Mk1 using a USDM rack, turned upside down, and then fitted all of the Mk2 pump and

control system, it worked but it was heavy and made the Mk1 feel funny to steer.” Mk1

refers to a 1985-89 MR2 and an Mk2 is a 1991-98 MR2. PAS stands for Power Assisted

Steering (8).

The next type of system is Electric Power Steering.

http://www.imoc.co.uk/


6

ELECTRIC POWER STEERING Electric Power Steering uses an electric motor that is attached directly to the steering

column or inside the steering rack, as seen in Figure 4 (5), and applies force to turn the

wheels. This motor is connected to a computer that reads signals from a torque sensor and

steering wheel angle sensor on the steering column and a signal of the vehicles speed, similar

to EHPS. It then calculates the amount of force needed for the motor to help turn the wheels.

The advantages of EPS are less components, light weight, quiet, not having any fluid to leak

making it maintenance free, increased life because it only runs when the steering wheel is

turning, does not use horse power that decreases fuel economy and can have the ability to

adjust the amount of overall assist to the user’s preference. The disadvantages are there needs

to be room to mount it somewhere on the steering column or rack and diagnostic tools are

needed if it malfunctions.

Figure 4 - Electric Power Steering

EPS is used mainly on hybrid vehicles that try to eliminate pollution such as hydraulic

fluid. These systems, however, are becoming popular as kits for vehicles that never came

with any type of power steering such as Unisteer’s Universal Electra Steer kit.


7

UNIVERSAL ELECTRA-STEER Unisteer is a company that sells steering components and kits. Figure 5 (9) shows a

universal electric power steering kit that includes the electric motor, control module, wiring

harness, hardware and a square universal bracket made to be modified as needed. Parts that

are not included in the kit but are available on their website are u-joints, couplers and

steering shafts.

Figure 5 – Universal Electra Steer

As mentioned earlier, Paul Woods put EHPS from a later generation MR2 on his early

generation MR2. He also has successfully put another power steering system on his car by

integrating EPS from another vehicle.

Bracket

Control Module

(ECU)

Steering

Rack

Electric Motor


8

ADJUSTABLE POWER STEERING On the website www.imoc.co.uk, there is a forum discussion started by Paul Woods

about his creation of a one-off power steering system for a 1985-89 Toyota MR2 where he

mated Vauxhall Corsa electric power assist parts into the MR2 steering column shown in

Figure 6 and Figure 7 (8). This system uses a custom lower knuckle joint from the column to

the rack. Small modifications needed to be made under the dash to make it fit. He also

installed a knob that allows him to vary the amount of assist and turn it off completely. The

system allows Woods to “park the car with fingertip control even with a stonking V8 and

huge tires.”

Figure 6 - Before Installation

Figure 7 - After Installation

The last type of power steering is Steer-By-Wire but is not fully developed for public roads.

Electric Motor

http://www.imoc.co.uk/


9

STEER-BY-WIRE Steer-By-Wire is basically the same concept as Electronic Power Steering only the

steering column is not connected with the steering rack as seen in Figure 8 (5). On the

steering wheel side is an angle sensor, steering wheel actuator and feedback motor. On the

rack side is the electric motor, pinion and pinion sensor. When the steering wheel is turned,

the actuator tells the electric motor to turn and stops when the pinion angle sensor reads the

same as the steering wheel angle sensor. The feedback motor gives the steering wheel

resistance proportional to the driving conditions. The advantages to Steer- By-Wire are

increased steering smoothness, parking and lane change assist and other vehicle designs. The

disadvantages are much greater cost.

Figure 8 – Steer-By-Wire

The end factor is that, although these Steer-By-Wire systems are on some industrial

vehicles, it is not fully safe for road legal vehicles. The safety redundancies are not fully

developed and if the system were to fail there is no other way of steering.

Based on the research, twelve features from the power steering systems stuck out the

most. The next step is to determine the features order of importance. They are then labeled as

Customer Features and put into a survey to decide the order of importance.


10

CUSTOMER FEEDBACK, FEATURES AND OBJECTIVES

SURVEY ANALYSIS The twelve features that are found to be most favored from the research are put into a

survey. The purpose of the survey is to determine the importance of the twelve customer

features that would be designed for in the creation of a power steering system for the 1985-89

Toyota MR2. The ratings are listed from 1-5 with 5 being the most important. It also asks

how much they are willing to pay for such a system by choosing a dollar amount range. The

survey is posted on the Toyota MR2 web forum, http://www.mr2.com, in which there are

fourteen responses. Table 1 shows that after analyzing the results, the importance of each

customer feature are no more than two percent different from the next. The two that tie for

the most important at eleven percent were Durability and Responsive Steering. The three

customer features that tie for least important are Safety, Low Steering Effort and Ease of

Installation. The cost of how much the respondents are willing to pay for the kit comes out to

about $800. (For the complete survey results see Appendix B)

Table 1 – Survey Results

With the customer features defined, Product Objectives are developed as a way to obtain

measurable results.

Customer FeaturesCustomer

Importance

Relative

Weight

Relative

Weight %

Durability 4.00 0.11 11%

Responsive Steering 4.00 0.11 11%

Weight 3.50 0.09 9%

Kit Completeness 3.36 0.09 9%

Ease of Maintenance 3.21 0.09 9%

Compatibility 3.14 0.08 8%

Quiet Operation 2.93 0.08 8%

Low Cost 2.86 0.08 8%

Ease of Installation 2.71 0.07 7%

Low Steering Effort 2.57 0.07 7%

Safety 2.43 0.07 7%

Energy Efficient 2.29 0.06 6%

http://www.mr2.com/


11

PRODUCT FEATURES AND OBJECTIVES The Product Features are the same as the customer features rated on the survey. They are

listed in order of most to least important in accordance with the survey. Under each feature

are Product Objectives. Product Objectives are goals in which to meet the customer features.

The customer features obtained are translated into measurable variables to determine if the

Product Objectives are met.

1. Durability 11%

a. All necessary components will be lubed

b. Materials will be corrosion resistant or painted

2. Responsive Steering 11%

a. Turning ratio will be 18:1 or smaller

3. Kit Completeness 9%

a. Kit will include all hardware

4. Weight 9%

a. Kit will weigh less than 40 lbs.

5. Ease of Maintenance 9%

a. Less than 8 steps

b. Less than 1 hour

6. Low Cost 8%

a. Prototype kit will cost less than $1750

7. Compatibility 8%

a. Will be compatible with a 1985-89 Toyota MR2

8. Quiet Operation 8%

a. Noise of power steering components will not exceed 40 decibels from driver’s

seat

9. Safety 7%

a. Kit will include cautionary notes for installation and maintenance

b. Steering wheel will have a maximum lash of 30mm

10. Low Steering Effort 7%

a. Force required to turn steering wheel will not exceed 15 lbs

11. Ease of Installation 7%

a. Will take less than 8 hours

12. Energy Efficient 6%

a. Will use less than 8% of engine horsepower

After coming up with Product Objectives, the next step is to analyze the importance of

each.


12

ENGINEERING CHARACTERISTICS The Product Objectives are then put in a Quality Function Deployment labeled as

Engineering Characteristics and are cross referenced with all the Product Features and

weights to see how important each is to the entire design. They are listed in Table 2 by

percentage in order of higher importance to lower with Materials having the most importance

and Standard Tools Used having the least importance. (For the complete Quality Function

Deployment see Appendix C)

Table 2 – Engineering Characteristics

After the importance of the Product Objectives and Engineering Characteristics are

realized, Design Alternatives and a Selection can be made.

Engineering Characteristics Importance %

Materials 14%

Weight (lbs) 13%

All Hardware Included (Y/N) 13%

Modifications Required (Y/N) 10%

Steps 8%

Time 8%

Standard Parts Used (Y/N) 7%

Steering Ratio 7%

Torque req. to turn wheel (ft*lbs) 6%

Lash (degrees) 5%

Loudness (db) 4%

Manufacturability 4%

Power usage (HP, Volts) 3%

Standard Tools used (Y/N) 3%


13

DESIGN ALTERNATIVES AND SELECTION The design alternatives are three of the four types of power steering, which are

Hydraulic, Electro-Hydraulic and Electric. To select to best design, the power steering

systems are rated on how well each would perform in completing the Product Objectives. It

is based on a 0-4 rating system. The power steering system that would perform best receives

a 4 and the others receive a rating relative to it. As shown in the Table 3, the Electric Power

Steering system outperforms or ties Hydraulic and Electro-Hydraulic in every Objective

except for cost, therefore Electric Power Steering is the chosen design.

Table 3 – Design Evaluations

The electric power steering converted column design consists of an upper shaft

assembly, electric motor and lower shaft assembly, shown in Figure 9, located between the

steering wheel and steering rack.

Figure 9 – Column Design

Power Steering

Design Evaluations

Wei

ght

Safety 0.07 3 0.21 3 0.21 4 0.28

Low Cost 0.08 4 0.32 4 0.32 3 0.24

Durability 0.11 3 0.33 3 0.33 4 0.44

Low Steering Effort 0.07 4 0.28 4 0.28 4 0.28

Responsive Steering 0.11 3 0.33 3 0.33 4 0.44

Kit Completeness 0.09 3 0.27 4 0.36 4 0.36

Weight 0.09 3 0.27 2 0.18 4 0.36

Energy Efficient 0.06 1 0.06 3 0.18 4 0.24

Ease of Installation 0.07 1 0.07 3 0.21 4 0.28

Compatibility 0.08 3 0.24 3 0.24 4 0.32

Quiet Operation 0.08 3 0.24 2 0.16 4 0.32

Ease of Maintenance 0.09 2 0.18 2 0.18 4 0.36

1.00 2.80 2.98 3.92

Elec

tric

Elec

tro

-Hyd

rau

lic

Hyd

rau

lic

Upper

Shaft

Assembly

Lower

Shaft

Assembly

Electric

Motor


14

LOADING CONDITIONS CALCULATIONS The stress put into the steering system is a torsional force caused by the driver twisting

the steering wheel to get the vehicle to turn and the tires resistance to turn. To find the

maximum turning force, a spring scale is used to turn the steering wheel as shown in Figure

10 (10) below. While the MR2 is parked on a concrete driveway a maximum force of 24 lbf

is applied at a distance of 6.5 inches from the center.

Figure 10 – Steering Effort

The stress concentration area is in the lower shaft assembly and is circled in the solid

model assembly in Figure 11. The electric motor will allow the driver’s input force to the

steering wheel not to exceed 15lbf by adding any additional force that would exceed that

amount. The total force applied through the lower shaft assembly will still be a maximum of

24 lbf. An exploded view in Figure 12 shows that the stress concentration area consists of a

coupler, rod, lower shaft and two pins.

Figure 11 – Solid Model Assembly

Figure 12 – Exploded Stress Area

Coupler

Rod

Lower Shaft

Pins


15

The maximum torsional stresses are located at the holes in the parts undergoing

torque. This stress is a result of the gross torsional stress multiplied by a stress concentration

factor. The gross torsional stress is found by using the torque, radius and polar moment of

inertia. The calculations below are for the Rod.

Equation 1 – Gross Torsional Stress

τgross =

=

Before the stress concentration factor can be found the force on the pins must be

known so a hole size can be chosen.

Equation 2 – Force on Pins

The stress concentration factor is found by taking the ratio of the hole diameter over

the Rod diameter and then following the number straight up until it comes to Curve C.

According to Figure 13 (11) a hole from .0625-.125in will provide the same stress

concentration factor.

Figure 13 – Stress Concentration Factor Graph


16

Equation 3 – Concentrated Stress Factor

Ktg @ .167 using Curve C = 3.75

The stress concentration factor and gross torsional stress are then multiplied to

produce the maximum torsional stress on the Rod.

Equation 4 – Max Torsional Stress

τmax = Ktg* τgross = 3.75*1.88 ksi = 7.06 ksi

The deflection in the Rod is found using the torque, length, shear stress modulus and

polar moment of inertia.

Equation 5 – Deflection

Θ =

A summary of the results for the component calculations is shown in Table 4. This

shows that the highest design stress is 14.1 ksi and the largest deflection is .0165 degrees in.

(For complete calculations see Appendix E)

Table 4 – Stress Analysis

Stress Analysis

Max

Stress

(ksi)

Safety

Factor

Design

Stress

(ksi)

Deflection

(deg.)

Rod 7.06 2.0 14.1 0.0003

Lower Shaft 4.24 2.0 8.5 0.0165

Coupler 1.50 2.0 3.0 0.0079


17

COMPONENT AND MATERIAL SELECTION The electric power steering system chosen is from Easysteer and is adjustable. Its

lowest setting requires and input force of 13.5 lbs. The system comes with many parts as

shown in Figure 14 (12), that allow for the buyer to adapt the system into most vehicles. The

parts list is as follows:

ECU with 2 feet of positive and negative 10 gauge wire

Electric Motor with 2 connectors

Upper steering column with internal splines

Ignition Barrel

Bracket

Universal Joint (not needed)

Control Box with wiring

40 Amp Fuse

7.5 Amp Fuse

Figure 14 - Easysteer


18

Since the highest design stress is only 14.1 ksi and the lowest yield strength for a

metal is 30 ksi any metal will suffice for each component. This means the stock column can

be used for the lower shaft. The coupler used has a round 0.75in hole on one side and a 0.75

DD hole on the other shown in Figure – 15 (13).

Figure 15 – Coupler

A .0625in 1070 steel pin, in Table 5 (14), has enough strength for the 416 lbs

of force but a .125in pin is chosen due to its extra strength and availability.

Table 5 – Spring Pins


19

The rod in Figure 16 (15) is made from 1018 mild steel with a yield strength of 53.7

ksi.

Figure 16 – Rod

A 2.5in diameter tubing is also needed to replace a smaller diameter portion of the

stock body so piece of 2.5 ID to 2.5OD Aluminized steel tubing, like in Figure 17 (16), is

readily available from the nearest Advanced Auto Parts Store.

Figure 17 – Tube


20

FABRICATION AND ASSEMBLY The stock steering column is, first, completely disassembled, as shown in Figure 18.

Figure 18 – Stock Column Disassembled

The body and shaft are both cut, as shown in Figure 19, into three sections; upper,

middle and lower sections. The middle sections are discarded as they are replaced by the

electric motor.

Figure 19 – Cutting the Stock Column

The side of the upper shaft from the MR2 that is cut is then grinded to form the chamfer

shown in Figure 20.

Figure 20 – Cut Upper Shaft


21

The splined section of the shaft from Easysteer is cut off and also chamfered and shown

in Figure 21.

Figure 21 – Splined Shaft

After the two parts are machined to a much closer diameter, the chamfered ends of the

splined shaft and the MR2’s upper shaft are butted against each other, clamped between two

v-blocks for concentricity and welded together. The new upper shaft assembly is able to fit

onto the steering wheel side of the electric motor as shown in Figure 22.

Figure 22 – Upper Shaft Assembly

A rod is milled down so half of it fits snuggly inside the lower shaft and the other side

into the DD coupler. A look at the test parts before assembly is shown in Figure 23.

Figure 23 – Lower Shaft Components


22

Two holes are drilled and a pin is pressed inside each. One hole is through the lower

shaft and rod and the other is through the coupler and rod so they cannot separate or rotate.

The new lower shaft assembly is fastened onto the rack side of the electric motor as shown in

Figure 24.

Figure 24 – Lower Shaft Assembly

The kit’s flange is cut off from the barrel and bolted down to the steering wheel side of

the electric motor. The upper stock body is bolted to the stock ignition barrel and is placed

over the new upper shaft until it touches the flange. The assembly is then bolted into the

MR2 as a test fit. The electric motor is rotated for best fitment and alignment marks are made

on the upper body and flange as shown in Figure 25. The assembly is then removed and the

upper body and flange are welded together.

Figure 25 – Alignment Marks


23

The hole of the bracket from Easysteer is bored out to match the tube and then bolted to

the steering rack side of the electric motor. The tube is inserted over the lower shaft assembly

and into the bracket. The lower body is bolted over the lower shaft assembly. The assembled

column is laid upside down with the flat part of the upper body and the flat part of the lower

body that gets bolted to the car rest on blocks as shown in Figure 26. The tube is tack welded

to the bracket and lower body then is removed from the rest of the column and is welded the

rest of the way around.

Figure 26 – Upper and Lower Body Alignment

The completed electric power steering column can be seen in Figure 27 and Figure 28.

Figure 27 – Power Steering Column Disassembled

Figure 28 – Power Steering Column Assembled


24

A hole is drilled in the lower dash panel for the adjustment knob and a portion of the

lower dash panel is cut where the electric motor interferes with it. The results are shown in

Figure 29.

Figure 29 – Knob Location

The ECU is installed behind the radio. The connectors from the electric motor and

control box are plugged into the ECU and the positive and negative 10 gauge wires are ran

from the ECU, under the carpet, through the firewall and to the battery. The column, dash

panel and steering wheel are then installed, as shown in Figure 30, and the MR2 is ready for

testing.

Figure 30 – Power Steering Column Installed

Adjustment

Knob

Cut-out


25

TESTING AND PROOF OF DESIGN The electric power steering system is tested to make sure each Product Objective is met.

The Power Steering System needs to be Lubed and Corrosion resistant and they are. The

column is inside the vehicle and will come in very little contact with moisture. The turning

ratio is to be 18:1 or smaller. This is measured with a protractor by dividing the change in

degrees of the steering wheel to the wheels which is a ratio of 18:1 and is unchanged.

The kit is to include all hardware to bolt the Power Steering System directly to the MR2’s

chassis and function and it does. Using a scale it weighs only 16 lbs which is less than the 40

lb maximum. The system’s maintenance is not to exceed eight steps and one hour. By using

an electric system it does not require any maintenance. The system is to be compatible with

the 1985-89 Toyota MR2 and it is. It bolts directly to the chassis in place of the old manual

column. The prototype cost $938 which is less than the forecasted amount of $1725 and that

includes all components and machining labor. The system is not to exceed a decibel reading

of 40 which is very noticeable to the human ear. During testing it makes no audible sound so

the use of a decibel meter is deemed unnecessary. Using a ruler the steering wheel lash

measures less than the 30mm limit at 23mm. The input steering effort required by the driver

does not to exceed the 15 lbs limit. With the adjustment knob set on the high setting, the

input effort does not exceed 7 lbs of force and with it set to its low setting the input effort

does not exceed 13.5 lbs of force. The installation time only takes about 4 out of the 8 hours

mainly due to running the battery wires under the carpet and back to the engine bay.

The electric motor uses a maximum horse power draw from the alternator of 0.410 HP and is

only 0.459% of the engines horsepower which is less than the 8.0% maximum.

Figure 31 – Effort of 7 lbs


26

SCHEDULE AND BUDGET

SCHEDULE The schedule measures 24 weeks long. It starts with the Proof of Design phase on

October 14th

and ends with the Final Project Report on April 15th

. Between these dates Table

3 shows the proposed and actual schedule of designing, modeling, bill of materials, ordering,

assembly and testing. The actual schedule took a few weeks longer but everything was

completed in time for the Tech Expo. (For the complete Schedule see Appendix E)

Table 6 – Schedule

TASKS

Analysis and Design of Steering Column

Analysis and Design of Pump

CAD Models

Bill of materials

Order parts

Assembly and Testing

Proposed

Actual

AprilNovember December Jan February March

Adam Close1985-89 MR2 Power Steering


27

BUDGET The budget is a list of every expense that is involved with the project. This includes

components and labor for machining. The total cost to fit the power steering to the car was

estimated to be about $1750 but ended up only costing $938.

Table 7 – Budget

Components Forcasted Cost Actual Cost

Pump 500.00$

Wiring, Relays,Fuses, etc. 50.00$

Computer 200.00$

Brackets 25.00$

Intermediate Shaft 75.00$

Universal Joint 75.00$

Steering Rack 500.00$ -

Fluid 50.00$ -

Fluid Reservior 100.00$ -

Pressure Lines 150.00$ -

DD Coupler - 19.49$

Pipe - 2.5" x 18" LG - 13.95$

Machining, welding,

rod, pins-

$375.00

TOTAL 1,725.00$ 938.44$

BUDGET

530.00$


28

RECOMMENDATIONS The electric motor chosen for this project is both large and much more powerful than is

needed for the MR2 but was chosen mostly due to the low price. The use of a smaller motor

would benefit by freeing up space for a heating and cooling duct alternative and also to

regain full range for the column to tilt. With the assist turned on high the driver only needs 7

lbf maximum to steer. At this level, the vehicle was very easy to turn but at speeds up to 35

mph it felt dangerous. The vehicle has not been driven at highway speeds at this level but is

highly recommended not be done. With the assist turned to low the driver needs a maximum

input force of 13.5 lbf and feels very comfortable but 15 lbf might be perfect. Therefore an

electric motor at half the capacity would be ideal.


29

WORKS CITED 1. Walker, Paula. Hamilton, September 9, 2012.

2. Walker, Jen. Cincinnati, September 9, 2012.

3. Close, Joyce. Cincinnati, September 9, 2012.

4. Close, Dan. Cincinnati, September 9, 2012.

5. Sclar, Deanna. Auto Repair for Dummies. Indianapolis : Wiley Publishing, Inc., 2009.

ISBN: 978-0-7645-9902-6.

6. 1965-70 Flaming River Power Steering Rack With Tilt Column. www.mustangplus.com.

[Online] [Cited: September 20, 2012.] http://www.mustangsplus.com/xcart/1965-70-

Flaming-River-Power-Steering-Rack-With-Tilt-Column.html.

7. Motoring News. www.webwombat.com. [Online] August 5, 2010. [Cited: October 17,

2012.] http://www.webwombat.com.au/motoring/news/news0028.htm.

8. Adjustable Power Steering. International MR2 Owners Club. [Online] [Cited: September

8, 2012.]

http://www.imoc.co.uk/forums/viewtopic.php?t=134255&postdays=0&postorder=asc&start=

0.

9. Universal Electra-Steer. www.unisteer.com. [Online] [Cited: September 8, 2012.]

http://www.unisteer.com/search_by_product/electric_power_steering/electra-steer.html.

10. Stationary Steering Force. Out-Club. [Online] [Cited: December 16, 2012.] http://faq.out-

club.ru/download/outlander-

III/maintenance/Service_Manual_2013/2013/37/html/M137200170120500ENG.HTM.

11. Mott, Robert L. Machine Elements in Mechanical Design. 4th. Upper Saddle River :

Pearson Prentice Hall, 2004. ISBN 0-13-061885.

12. Electric Power Steering Kit. Photobucket.com. [Online] mk2mania. [Cited: December 20,

2012.]

http://s187.photobucket.com/user/mk2mania/library/electric%20power%20steering%20kit?s

ort=3&page=1.

13. Borgeson 315249 3/4" DD x 1" DD Steel Steering Coupler. Sears.com. [Online] [Cited:

December 22, 2012.] http://www.sears.com/borgeson-315249-3-4inch-dd-x-1inch-dd-steel/p-

SPM6384329308?prdNo=7.

14. PinsRollSpring. fastenersuperstore.com. [Online] [Cited: December 28, 2012.]

http://www.fastenersuperstore.com/productSheets/PinsRollSpring.pdf.

15. 1018-steel-round-rod-750-diameter-x-48-long. onlinemetalsupply.com. [Online] [Cited:

December 28, 2012.] http://www.onlinemetalsupply.com/steel/steel-round-rod/1018-steel-

round-rod-750-diameter-x-48-long.html.

16. 3A-Racing-3-in-i-d-x-18-in-length-tailpipe-extension. autozone.com. [Online] [Cited:

December 16, 2012.] http://www.autozone.com/autozone/accessories/3A-Racing-3-in-i-d-x-

18-in-length-tailpipe-extension/_/N-257z?itemIdentifier=258995&_requestid=315229.

Appendix A1

APPENDIX A - RESEARCH

Interview with daily commuter, September 9, 2012

Paula Walker of 735 Gordon Smith Blvd, Hamilton, Ohio 45013

Use to drive a 1956 Buick Special that had a semi truck size steering wheel and no

power steering.

Feels that non-power steering is not difficult on city streets except when parallel

parking.

Says vehicles with power steering are much easier to drive all-around.

Prefers modern size steering wheel and power steering.


Joyce Close of 767 West Pekin Road, Lebanon, Ohio 45036

Has driven a 1995 Ford Van and a 2000 Ford 350 Truck in which both power steering

systems developed play. Wants reliable power steering.

Interview with daily commuter and racecar driver, September 9, 2012

Dan Close of 767 West Pekin Road, Lebanon, Ohio 45036

Prefers daily driver to have low steering effort and racecar to have responsive steering.


Jen Walker of 8421 Haskell Road, Cincinnati, Ohio 45239

Likes power steering with responsive handling.

Appendix A2

Universal Electra-Steer

If you have ever dreamed of having the ability to allow your engine

more horsepower at the flick of a switch or ease the pain of

maneuvering a tough spot at the local cruise night then you need to

check out Electra-Steer by Unisteer. Electra-Steer is a compact

electric power assist unit that decreases steering effort up to 35%

compared to manual steering. They work off of the vehicles already

existing 12 volt system without any modifications and go right in

line with your steering shaft. The vehicle must use a steering wheel

and not exceed a total weight of 3,000 lbs.

Universal kit includes:

Electric motor

Control module

Wiring harness

Square universal mount bracket

Hardware

Universal kit does not include

U-joints

Couplers

Steering shaft

Universal

Compact

Can be turned off

Does not use

horsepower

Does not come

with everything

needed

Cost $995.00

http://www.unisteer.com/se

arch_by_product/electric_p

ower_steering/electra-

steer.html 9/8/12

Universal Electra-Steer

www.unisteer.com

http://www.unisteer.com/search_by_product/electric_power_steering/electra-steer.html




Appendix A3

Adjustable Power Steering

Forum discussion started by Paul Woods about his creation of a

one-off power steering system for a 1985-89 Toyota MR2

mating Vauxhall Corsa electric power assist parts into the MR2

steering column.

Uses a custom lower knuckle joint from column to rack.

Slight alterations under the dash need to be made for fitment.

Can be turned off or vary the amount of assist with knob he

installed on the dash.

Can park the car with fingertip control even with a V8 and wide

tires.

Variable amount of

assist

Fingertip Control

Unknown cost of parts

Not all parts used are

known

Not a kit

http://www.imoc.co.uk/foru

ms/viewtopic.php?t=134255

&postdays=0&postorder=asc

&start=0 9/8/12 Adjustable

Power Steering

www.imoc.co.uk

http://www.imoc.co.uk/forums/viewtopic.php?t=134255&postdays=0&postorder=asc&start=0




Appendix A4

MK2 Powered MK1 MR2

In a forum discussion where Paul Woods incorporates Corsa

power assisted steering into a 1985-89 Toyota MR2 steering

column he mentions, “A few years ago I retro fitted a Mk2

PAS system onto a Mk1 using a USDM rack, turned upside

down, and then fitted all of the Mk2 pump and control

system, it worked but it was heavy and made the Mk1 feel

funny to steer. There was no adjustability in that setup at

all.” Mk1 refers to a 1985-89 MR2 and an Mk2 is a 1991-98

MR2. PAS stands for Power Assisted Steering.

Used parts from later

model

Parts too heavy

Made steering feel funny

http://www.imoc.co.uk/forums/vie

wtopic.php?t=134255&postdays=0

&postorder=asc&start=0 9/8/12

Adjustable Power Steering www.imoc.co.uk




Appendix A5

Flaming River Power Steering Rack With Tilt Column

Add power steering to your classic Mustang. These Flaming

River 1965-70 Mustang power rack and pinion conversion kits

are designed to give you driving comfort, especially when

parking. They feature a cradle that mounts in the original

chassis location with no modification, and the center support

does not have to be removed. The kits include: a new tilt

steering column with universal joints, shafting, support bearing,

billet aluminum reservoir, power rack and pinion, and mounting

cradle. They also include all grade 8 mounting hardware and a

variable pressure pump for true-steering driving performance.

Kit is complete

Easy to park

No modifications to

intended vehicle

Cost $1,999.95

http://www.mustangsplus.com/xcart/1965-

70-Flaming-River-Power-Steering-Rack-

With-Tilt-Column.html 9/20/2012 1965-70

Flaming River Power Steering Rack With

Tilt Column

www.mustangplus.com

http://www.mustangsplus.com/xcart/1965-70-Flaming-River-Power-Steering-Rack-With-Tilt-Column.html



Appendix A6

Slightly less compact

than non-powered

steering rack

Would decrease fuel

economy by using

the motor to power

the pump

Auto Repair for Dummies,

(2009) pg. 296

Appendix A7

Electro-Hydraulic Power Steering For the first time in the world, an Electro-hydraulic Power Steering

system has been adopted in which the motor is activated only when

the driver is steering. The system is smaller than traditional power

steering systems, which was achieved by integrating multiple parts.

It offers the advantages of both types of steering - the natural and

smooth steering of hydraulic power steering and the improved fuel

efficiency of electric power steering - combined to create a balanced

system fitting the Nissan Fuga and Infiniti M’s luxury sport sedan

buyers’ needs.

Natural and

smooth steering

Smaller than

Hydraulic Power

Steering

Improved fuel

efficiency

Leaks

Requires routine

maintenance.

http://www.webwombat.com.au/mot

oring/news/news0028.htm

10/17/2012 Motoring News

www.webwombat.com

http://www.webwombat.com.au/motoring/news/news0028.htm

http://www.webwombat.com.au/motoring/news/news0028.htm

Appendix A8

No modification to

steering rack

Compactness

depends on of size of

motor

Electric motors have

a moderate to high

cost


(2009) pg. 297

Appendix A9

Light weight

Steers smoothly

Reduces chance of

mechanical failure

Will not decrease fuel

economy

Very high cost

Not completely

reliable or safe on road

vehicles yet


(2009) pg. 299

Appendix B1

APPENDIX B - SURVEY

POWER STEERING FOR 1985-89 MR2

CUSTOMER SURVEY

The purpose of this survey is to determine the importance of each feature that will be

designed for in the creation of a power steering system for the 1985-89 Toyota MR2.

How important is each feature to you for the design of a power steering system?

Please circle the appropriate answer. 1 = low importance 5 = high importance

Avg.

Safety 1(4) 2(2) 3(2) 4(5) 5 N/A(1) 2.43

Low cost 1(3) 2(2) 3(1) 4(5) 5(2) N/A(1) 2.86

Durability 1(2) 2 3(1) 4(4) 5(7) N/A 4.00

Low steering effort 1(6) 2(1) 3(1) 4(5) 5(1) N/A 2.57

Responsive steering 1(3) 2 3 4(2) 5(9) N/A 4.00

Kit Completeness 1(3) 2 3(1) 4(4) 5(5) N/A(1) 3.36

Weight 1(3) 2(3) 3(2) 4(1) 5(6) N/A 3.50

Energy efficient 1(5) 2(2) 3(2) 4(3) 5(1) N/A(1) 2.29

Ease of installation 1(3) 2(1) 3(4) 4(4) 5(1) N/A(1) 2.71

Compatibility 1(3) 2(1) 3(1) 4(4) 5(4) N/A(1) 3.14

Quiet operation 1(3) 2(2) 3(2) 4(2) 5(4) N/A(1) 2.93

Ease of Maintenance 1(3) 2 3(2) 4(4) 5(4) N/A(1) 3.21

37.0

How much would you be willing to pay for a product like this?

Avg.

$100-$200(5) $200-$500(5) $500-$1000(2) $1000-$2000 $2000-$5000(1) $800

Thank you for your time.

Appendix C1

APPENDIX C – PRODUCT OBJECTIVES Product Objectives are goals in which to meet the customer requirements. The customer requirements

obtained are translated into measurable variables which determine if the Product Objectives are met.

1. Durability 11%

a. All necessary components will be lubed

b. Materials will be corrosion resistant or painted

2. Responsive Steering 11%

a. Turning ratio will be 18:1 or smaller

3. Kit Completeness 9%

a. Kit will include all hardware

4. Weight 9%

a. Kit will weigh less than 40 lbs.

5. Ease of Maintenance 9%

a. Less than 8 steps

b. Less than 1 hour

6. Low Cost 8%

a. Prototype kit will cost less than $1750

7. Compatibility 8%

a. Will be compatible with a 1985-89 Toyota MR2

8. Quiet Operation 8%

a. Noise of power steering components will not exceed 40 decibels from driver’s

seat

9. Safety 7%

a. Kit will include cautionary notes for installation and maintenance

b. Steering wheel will have a maximum lash of 30mm

10. Low Steering Effort 7%

a. Force required to turn steering wheel will not exceed 15 lbs

11. Ease of Installation 7%

a. Will take less than 8 hours

12. Energy Efficient 6%

a. Will use less than 8% of engine horsepower

Appendix D1

APPENDIX D – QUALITY FUNCTION DEPLOYMENT

Lash (

degre

es)

Sta

ndard

Part

s u

sed (

Y/N

)

Weig

ht

(lbs)

Torq

ue r

eq.

to t

urn

wheel (f

t*lb

s)

Turn

ing R

atio (

ratio o

f deg.)

All

Hard

ware

inclu

ded (

Y/N

)

Mate

rials

Manufa

ctu

rabili

ty

Pow

er

usage (

HP

, V

olts)

Ste

ps (

#)

Tim

e (

hrs

.)

Sta

ndard

Tools

used (

Y/N

)

Modific

ations R

eq.

(Y/N

)

Loudness (

db)

Custo

mer

import

ance

Rela

tive w

eig

ht

Rela

tive w

eig

ht

%

Safety 9 1 3 1 2.43 0.07 7%

Low Cost 9 3 9 9 9 2.86 0.08 8%

Durability 3 9 4.00 0.11 11%

Low Steering Effort 1 9 3 2.57 0.07 7%

Responsive Steering 3 3 3 9 4.00 0.11 11%

Kit Completeness 9 1 3.36 0.09 9%

Weight 9 9 3.50 0.09 9%

Energy Efficient 9 2.29 0.06 6%

Ease of Installation 3 9 9 9 9 3 9 2.71 0.07 7%

Compatibility 1 1 9 3.14 0.08 8%

Quiet Operation 9 2.93 0.08 8%

Ease of Maintenance 1 9 9 3 3 3.21 0.09 9%

Abs. importance 0.92 1.32 2.29 1.15 1.25 2.26 2.52 0.70 0.56 1.44 1.44 0.48 1.77 0.71 17.88 37.0 1.0 1.0

Rel. importance 0.05 0.07 0.13 0.06 0.07 0.13 0.14 0.04 0.03 0.08 0.08 0.03 0.10 0.04 1.00

Adam Close

1985-1989 MR2 PowerSteering Kit

9 = Strong3 = Moderate1 = Weak

Appendix E1

APPENDIX E – CALCULATIONS

ROD

Torsional Stress

τmax =

=

Deflection

Θ =

Torsional stress at hole

Ktg @ .167 = 3.75


LOWER SHAFT

Torsional Stress

τmax =

=

Appendix E2

Deflection

Θ =


Ktg @ .125 = 3.65


COUPLER

Torsional Stress

τmax =

=

Deflection

Θ =


Ktg @ .1 = 3.20

τmax = Ktg* τgross = 3.20*.467 ksi = 1.50 ksi

FORCE ON PINS

Appendix E3

POWER STEERING MOTOR

Horsepower usage from power steering

Percentage of Engine Horsepower

Appendix F1

APPENDIX F – SCHEDULE

TASKS Oct

14

-20

Oct

21

-27

Oct

28

- N

ov

3

No

v 4

- 1

0

No

v 1

1 -

17

No

v 1

8 -

24

No

v 2

5 -

Dec

1

Dec

2 -

8

Dec

9 -

15

Dec

16

- 2

2

Dec

23

- 2

9

Dec

30

- J

an 5

Jan

6 -

12

Jan

13

- 1

9

Jan

20

- 2

6

Jan

27

- F

eb 2

Feb

3 -

9

Feb

10

- 1

6

Feb

17

- 2

3

Feb

24

- M

ar 2

Mar

3 -

9

Mar

10

- 1

6

Mar

17

- 2

3

Mar

24

- 3

0

Mar

31

- A

pr

6

Ap

r 7

- 1

3

Ap

r 1

4 -

20

Ap

r 2

1 -

27

Proof of Design to advisor 22

22

Concept sketches to advisor 22

22

Report 29

29

Analysis and Design of Steering Column 5

15

Model Steering Column 12

15

Analysis and Design of Motor 19

15

Model Motor 26

15

Design Freeze 15

15

Bill of materials 15

15

Order parts 15

3

Oral Report 13

13

Design Report to Advisor 13

13

Assembly and Testing 24

24

Demo to Advisor 25

Expo 4

4

Final Oral Report 16

16

Project Report 21

21


Appendix G1

APPENDIX G - BUDGET


Pump 500.00$


Computer 200.00$

Brackets 25.00$




Fluid 50.00$ -



DD Coupler - 19.00$

Pipe - 2.5" x 18" LG - 14.00$

Machining, welding, rod,

pins-

$375.00

TOTAL 1,725.00$ 938.00$

BUDGET

530.00$

Appendix H1

APPENDIX H – DRAWINGS

Appendix H2

Appendix H3

Appendix H4

Appendix H5

Appendix H6

Appendix H7

Appendix H8

Appendix H9

Appendix H10

Appendix H11

Appendix H12

Appendix H13

Appendix H14

Appendix H15

Appendix I1

APPENDIX I – PRESENTATION

By Adam Close Advisor: Prof. Dave

Appendix I2

Problem Definition and Background

1985-89 MR2

Small 2-seater = Great Commuter

No power steering = Difficult to maneuver at low speeds and take slightly longer to park

I will enable the MR2 to be parked using one hand

Appendix I3

Four Types of Power Steering

Hydraulic

Electro-Hydraulic

Electric

Steer-by-Wire

Appendix I4

Hydraulic Power SteeringEngine driven hydraulic pump Most common

Least compact

Decreases fuel economy and horsepower

Leaks over time

Requires routine maintenance

Appendix I5

Electro-Hydraulic Power Steering Electric motor driven

pumpMostly on mid-engine

vehicles

Smaller than hydraulic

Leaks over time

Requires routine maintenance.

Appendix I6

Electric Power SteeringElectric motor integrated into the

steering columnHybrid vehicles

Very Compact

No leaks

No maintenance

Appendix I7

Steer-By-Wire Electric motors on steering wheel

side and rack side

No physical link

Angle sensors

Feedback sensor

Boats and forklifts

Very Compact

Reduces chance of mechanical failure

Very high cost

Not completely reliable or safe on road vehicles yet

Appendix I8

Survey Analysis Twelve features

from interviews and types of P/S

Posted on car forum mr2.com

Fourteen responses

Average willing to pay $800 for a kit

Customer FeaturesCustomer

Importance

Relative

Weight

Relative

Weight %

Durability 4.00 0.11 11%

Responsive Steering 4.00 0.11 11%

Weight 3.50 0.09 9%

Kit Completeness 3.36 0.09 9%

Ease of Maintenance 3.21 0.09 9%

Compatibility 3.14 0.08 8%

Quiet Operation 2.93 0.08 8%

Low Cost 2.86 0.08 8%

Ease of Installation 2.71 0.07 7%

Low Steering Effort 2.57 0.07 7%

Safety 2.43 0.07 7%

Energy Efficient 2.29 0.06 6%

Appendix I9

Measureable Objectives

Weigh less than 40 lbs.

Cost less than $1725 to produce prototype

Not exceed 40 decibels from driver’s seat

Steering wheel will have a maximum lash of 30 mm

Steering effort will not exceed 15 lbs

Use less than 8% of engine horsepower

Appendix I10

Engineering Characteristics

Importance determined using House of Quality

Each Engineering Characteristic rated in importance against each feature (if applied) with a 1, 3 or 9 with 9 being the highest

Total of 100%

Engineering Characteristics Importance %

Materials 14%

Weight (lbs) 13%

All Hardware Included (Y/N) 13%

Modifications Required (Y/N) 10%

Steps 8%

Time 8%

Standard Parts Used (Y/N) 7%

Steering Ratio 7%

Torque req. to turn wheel (in*lbs) 6%

Lash (mm) 5%

Loudness (db) 4%

Manufacturability 4%

Horsepower usage 3%

Standard Tools used (Y/N) 3%

Appendix I11

Selection Process Determined which

power steering type performed best with the Objectives

Based on 0-4 rating system with 4 being best

Scores are relative to each other

Electric wins all but cost

Power Steering

Design Evaluations

Wei

ght

Safety 0.07 3 0.21 3 0.21 4 0.28

Low Cost 0.08 4 0.32 4 0.32 3 0.24

Durability 0.11 3 0.33 3 0.33 4 0.44

Low Steering Effort 0.07 4 0.28 4 0.28 4 0.28

Responsive Steering 0.11 3 0.33 3 0.33 4 0.44

Kit Completeness 0.09 3 0.27 4 0.36 4 0.36

Weight 0.09 3 0.27 2 0.18 4 0.36

Energy Efficient 0.06 1 0.06 3 0.18 4 0.24

Ease of Installation 0.07 1 0.07 3 0.21 4 0.28

Compatibility 0.08 3 0.24 3 0.24 4 0.32

Quiet Operation 0.08 3 0.24 2 0.16 4 0.32

Ease of Maintenance 0.09 2 0.18 2 0.18 4 0.36

1.00 2.80 2.98 3.92

Elec

tric

Elec

tro

-Hyd

rau

lic

Hyd

rau

lic

Appendix I12

Electric Power Steering Products Available

Flaming River

Unisteer

Easysteer

All products come with Motor, CPU, most wiring.

Appendix I13

Flaming RiverPros

Input effort = 13.5 lbs

Adjustable Assist

90 Day Warranty

Cons

$5950.00 + Shipping

Large motor

Appendix I14

UnisteerPros

Lifetime Warranty

$995 + Shipping

Cons

Assist not adjustable


Appendix I15

EasysteerPROS


Adjustable Assist

Lifetime Warranty

$400.00 + Shipping

CONS

Large motor

Appendix I16

Loading Conditions

24 lbs Max@ 6.5 in

Appendix I17

Loading ConditionsSteering wheel side

Rack side

Power Steering Motor

Concentrated stress area

Appendix I18

Solid Model Exploded Assembly

CouplerRod

Lower Shaft

Pins

Appendix I19

Equations for Torsional Stress

Appendix I20

Sample CalculationsROD Torsional Stress = = 24 6.5 = 156

=

2=

.75

2= .375

=

32 4 =

32 (.75 )4 = .0311 4

τmax =

=

156 .375

.0311 4 = 1.88

Deflection

Θ = 𝐿

𝐺 =

156 .75

11.5 106 / 2 .0311 4

180

= .000327

Appendix I21

Method for Stress Around Holes

Appendix I22

Sample Calculations


= .

125

. 75= .167

Ktg @ .167 = 3.75 τmax = Ktg* τgross = 3.75*1.88 ksi = 7.06 ksi

Appendix I23

Stress Table

Stress AnalysisMax Stress

(ksi)

Yield

Strength (ksi)

Safety

Factor

(>2.0)

Deflection

(deg.)

Rod - 1018 Mild Steel 7.06 53.7 7.6 0.0003

Lower Shaft - (assuming

1020 Hot-rolled steel)4.24 30.0 7.1 0.0165

Coupler - (assuming 1020

Hot-rolled steel)1.50 30.0 20.1 0.0079

Appendix I24

Sample Calculations

FORCE ON PINS

=

=

156

. 75 = 208

Stress AnalysisMax Force

(lbs)

Yield

Strength (lbs)

Safety

Factor

Spring Pin

(Carbon Steel, 1/8 in)208 1875 9.0

Appendix I25

Component and Material Selection

DD Coupler

Rod

Spring Pins

Appendix I26

DD Coupler Borgeson Universal

Steering Shaft Coupler

Steel, 3/4 in DD, 3/4 in

Cost $19.49

Appendix I27

Rod Dreier Tool & Die Corp.

1018 Mild Steel, ¾ in. Diameter, 2 in. Long

Free with machining service

Appendix I28

Spring Pins Dreier Tool & Die Corp.

Carbon Steel, 1/8 in. Diameter, 2 in. Long

Free with machining service

Appendix I29

Planned Fabrication & AssemblyUpper column to power steering motor:

Butted upper column to spline shaft

Welded between two V-blocks for concentricity

Mounted onto power steering motor

Appendix I30

Planned Fabrication & AssemblyPower steering motor to lower column:

Attached coupler to power steering motor

Inserted ¾ in. rod into coupler

Placed lower column over rod against coupler

Drilled 1/8 in. hole through coupler and rod

Inserted 1/8 in. pin

Drilled 1/8 in. hole through lower column and rod

Inserted 1/8 in. pin

Appendix I31

Testing & Proof of Design

Objective Test Method Results Pass/Fail Importance

Lubed and Corrosion resistant Visual Yes Pass 11%

Turning Ratio 18:1 or smaller Protractor 18:1 Pass 11%

Kit includes all hardware Visual Yes Pass 9%

Weighs less than 40 lbs Weight Scale 16 lbs Pass 9%

Maintenance less than 8 steps, 1 hour Clock 0 steps, 0 hours Pass 9%

Costs less than $1725 to make Calculator $938 Pass 8%

Compatible with 1985-89 MR2 Visual Yes - 8%

Does not exceed 40 decibels Decibel Meter 0 Pass 8%

Steering wheel will have a maximum lash

of 30 mmRuler 23 mm Pass 7%

Steering effort does not exceed 15 lbs Fish Scale 7 lbs Pass 7%

Installation should take less than 8 hours Clock 4 hours Pass 7%

Use less than 8% of engine horsepower Engine Dyno 0 hp Pass 6%

Appendix I32

Compatibility

New power steering column bolts directly to frame in place of old one but due to the large motor:

Tilt is decreased by 50%

One of the heating and cooling ducts has to be removed with no room for a replacement

Dash panel needs a portion cut out

Appendix I33

Recommendations

A smaller power steering motor could allow:

full tilt

flexible replacement for heating and cooling duct

Possibly an uncut dash panel

Appendix I34

Schedule Discussion (Proposed/Actual)

TASKS

Analysis and Design of Steering Column

Analysis and Design of Pump

CAD Models

Bill of materials

Order parts

Assembly and Testing

Proposed

Actual

November December Jan February March


Appendix I35

Budget


Pump 500.00$


Computer 200.00$

Brackets 25.00$




Fluid 50.00$ -



DD Coupler - 19.49$

Pipe - 2.5" x 18" LG - 13.95$

Machining, welding,

rod, pins-

$375.00

TOTAL 1,725.00$ 938.44$

BUDGET

530.00$

Appendix I36

Questions?

Appendix J1

APPENDIX J – WIRING DIAGRAM

ECU

Electric

Motor

Control

Box

Adjustable

Knob

7.5 Amp

Fuse

40 Amp

Fuse

Battery

Ground

12v

(radio acc)

Multiple Wires with Connecter

10 Gauge Positive

10 Gauge Negative

18 Gauge Positive

18 Gauge Negative

Appendix K1

APPENDIX K – WIRE ROUTING

1985-89 toyota mr2 power steering - uc drc home

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