Bottom Steering Rack Component Decision Matrix

Status

In Progress

Owner

@Gerard Cardenas

Contributors

@Philip Bortolotti @Cesar Hernandez

Approved

Due date

Jun 2, 2024

Decision

We will use a coupler for the pinion input, two 5/8” OD intermediate and output hollow steel shafts, and steel 5/8-36 X 5/8 smooth bore u joints. The sequence of the assembly is as follows:

 

Steering rack → 5/8”-36 spline coupler → 5/8” OD shaft → set screwed into the spline side of a 5/8”-36 spline u joint → smooth bore side welded onto 5/8” OD intermediate shaft → intermediate shaft welded onto smooth bore side of second 5/8” u joint → spline side of u joint set screwed onto steering wheel input shaft

On this page

 

 Problem statement


There are many options for components linking the steering wheel to the rack. This decision matrix is to decide the best option for each component.

 Research insights


 Solution hypothesis


 

 

 Design options

  •  

Output Shaft to Coupler

Option 1

Option 2

Option 3

Output Shaft to Coupler

Option 1

Option 2

Option 3

Overview

Use a 5/8” OD shaft with a through hole to fix inside of splined coupler with bolt

Use a 5/8” OD steel shaft, insert shaft into coupler, and weld side of shaft onto edge of the coupler

Use a greater diameter steel shaft and weld edge of the shaft to the edge of the coupler

Screenshot

 

 

Link

 

 

Benefits and risks

Relatively easy to manufacture - no need for welding

No need for a special shaft (splined shaft or DD shaft)

Constraining with a bolt going through a through hole can deform the shaft (might have to use steel)

A stronger alternative to using a bolt to constrain shaft

Need to use steel to weld onto the coupler

Coupler steel grade not specified, may be risky to weld

Opens up the opportunity to use a u joint that has a shaft diameter other than 5/8”

Coupler steel grade not specified, may be risky to weld

Criteria

 

 

 

 

U-joint

Option 1

Option 2

Option 3

U-joint

Option 1

Option 2

Option 3

Overview

Smooth Bore

Spline

DD Shaft

Screenshot

image-20240602-195310.png

 

image-20240602-195502.png

 

 

 

Link

 

 

Benefits and risks

Can accommodate regular smooth pipes - no need for special shaft (spline shaft or D shaft)

Only way to constrain the shaft is to weld the shaft onto the u joint - shaft needs to be same material as the u joint

No need to drill extra holes

May be difficult to find a spline shaft (at least in the desired size)

Shaft cannot be hollow - adds weight

No need to drill extra holes

May be difficult to find a double d shaft (at least in the desired size)

Shaft cannot be hollow - adds weight

Criteria

 

 

 

 

 Follow up

Decision

Status

Next steps

Decision

Status

Next steps

decided / in review / other

 

 

 

 

 Source files

Type /link to add links to design files.