Page Comparison

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• The telescoping mechanism allows the linear distance of the steering wheel to be adjusted by the driver.
• This system adjusts incrementally. It is not infinitely adjusting.
  • Infinitely adjusting systems allow for the shaft to be adjusted to any distance within a given range. Incremental adjusting systems only allow the user to adjust to specific locations along the shaft.
  • An infinitely adjusting system was not used; a significant amount of friction would have been required to allow the telescoping shaft to rotate without backlash (at the exact same speed as the collapsible column).
• Backlash or play is expected with this system. This must be resolved. As per the design meeting on 9/19/2019, the spring plungers can be biased in a certain direction by being pushed sideways (i.e. not axially) to stay in place and minimize backlash.is resolved by using a D-shaft (from here) for the telescoping mechanism.
  • A D-shaft was chosen arbitrarily out of the choices of non-circular shafts. Either a D-shaft, a keyed shaft, or a splined shaft could have been used.
• The current design uses 2 1 spring plungersplunger (from here) which are is initially loaded in compression. They fit into conical holes that help to center the spring plunger nose within the holesIt fits into holes spaced ____mm apart. 
  • The hole spacing is arbitrary.
  • The hole is not conical since it does not significantly reduce backlash if the hole aids the spring plunger in centering itself within the hole. The main thing which aids against rotational backlash if the non-circular telescoping shaft.
• The spring plungers will act as the shear pins required for collapsibility in the event of a collision.
  • In a collision, the force will travel through the front of the car to the lower column (held in place by the steering column mounting), through the U-joint, and through the upper column, which will cause the spring plungers to fail by the shear stress loading. This prevents the driver from being impaled.
  A friction-based mechanism would allow for infinite adjustment; however, this requires a very large friction force to ensure that no components are slipping. The existing design could be improved by incorporating friction along with the spring plungers
• The collapsible column holds the telescoping shaft in place. The spring plunger is attached outside of it using a mount.
  • The mount is to be manufactured out of a small piece of metal.
  • The collapsible column is D-shaped (both inside and out). It may be manufactured via the following process:
    1. Make a hole axially through the shaft.
    2. From one side, mill the hole to have a D-shape. Repeat with the other side. This is done in 2 parts since the shaft may be too long to be milled in one step.
    3. Mill off the top surface to be flat.
    4. Tap a ___mm diameter hole through the side for the spring plunger to go through.
    5. Tap 4 more holes of __mm diameter for the mounting part to sit on.
    6. Screw on the mount with the plunger inside.

Tilt Mechanism

• The tilt mechanism is used to adjust the angle of the upper column and steering wheel by raising upper column. It allows the upper column to rotate about the U-joint.
• The tilt mechanism is also used as a part of the steering column mounting.

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