An automotive manufacturer of an ADA (American Disabilities Act) compliant vehicle ramp needed a motor to enable someone in a wheelchair to easily enter and exit the vehicle. It was critical that the ramp have a zero-failure rate with a manual override option since the ramp comes out of the floor and lowers to the ground, allowing wheelchairs to have a smooth transition from the ground onto the ramp and into the vehicle. In order to accurately position the height of the ramp, Groschopp added a two channel encoder to send feedback to the motor.
Knowing that the motor would see a range of weather and road conditions, cold temperature bearings, a watertight cord connector with custom crimping, and increased ingress protection were essential to the motor design. An additional obstacle with this project was that Groschopp’s motor needed to mate to an existing gearbox the customer had. This was achieved with a custom bolt-hole pattern with a tighter tolerance than standard.
Challenges
- 1,200 lb capacity
- Temperature range from -40°C to 60°C
- Able to withstand vibrational shock loads
- Harsh environmental/road conditions
- Secondary custom output shaft to integrate with the encoder
Solution
- PM8018 12v motor with a custom bolt-hole patterns
- Closed-loop control to provide feedback on the position of the ramp
- Tight tolerances on the output shaft and pilot to mate to the provided gearbox
- Cold temperature bearings and IP54 rated construction