Design Fall 2019/Winter 2020

CAD Design (April 2020)

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Changes from Spring/Fall 2019

• Removed clevis to make manufacturing easier.

• Created connections(mounts) to chassis.

• Found new rack in bay (unknown PN) approx. 130mm of travel.

• Design geometry has been subjected to FEA.

• Detailed design of all components.

• Converted design into master driven.

• Most fasteners are various lengths of M6/M8.

Steering Geometry

• It was found the most optimal way to achieve perfect Ackerman is to align the steering arm at the same angle as the line that connects the intersection of the track and wheelbase to the middle of the back wheelbase line.

• Model of Ackerman can be found: GrabCAD\MSXIV\Development\Dynamics\Steering

  • In the file “Ackerman 2D model” or “Overlay”.

  • Overlay contains the master sketch with the Ackerman model.

• ~88.67mm of travel in rack of model when at perfect Ackerman (~27 degrees).

Steering Column

• Collapse occurs in the upper column, with min ~3in of travel.

• Includes u-joint to allow the unit to tilt, unknown if this will be pursued.

Tie Rod

• Design similar to push rod.

• VR3 tube used in the middle with threaded components welded on the sides.

• Welded components are machined and give greater freedom in thread sizes (vs VR3 tube ID).

Rack Mount

• An angled rack mount was created to accommodate the angle at which a driver holds the steering wheel.

• By putting in an angled mount it allows the driver to angle their wrists down as opposed to up when driving.

• Tilting the wrist down occurs whenever the perpendicular to the rack is above the steering wheel point.

Interference Check

• Found in the MAX UP and MAX DOWN configurations in ASSEM-Dynamics.

• Centerlink is fixed to move only horizontally, there is a distance mate which sets the centerlink right plane 90mm (max travel) from the right plane of the assembly.

• See Video below.

Steering Intro Spring 2020

Link

Finalized CAD (May 30, 2020)

Bump Steering Characteristics

Note, a travel of 90mm was used for convenience.

• Bump steer was characterized using mates of an assembly between the upright and steering system.

• The upright was moved up or down to simulate moving past a bump

• The centerlink was moved 90mm to simulate the largest angles the wheels would be allowed to turn at

• The above chart is used to compare the difference in wheel angles when a bump is encountered vs the upright at a neutral position

• The spindle face was measured against the right plane to obtain measurements

• As can be seen, the difference in wheel angle is trivial

DRI