Wheel + Trans diff + Torsion bar?

Click For Summary

Discussion Overview

The discussion revolves around the design considerations for a four-motor electric vehicle (EV) that incorporates a differential with a torsion bar on one side of the CV axle. Participants explore the implications of this setup on power delivery and performance, addressing both theoretical and practical aspects of the proposed idea.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes using a torsion bar in the opposing side of the CV axle but questions how this would affect power delivery to the wheel and overall performance.
  • Another participant explains that locking one side of a differential causes the other side to rotate at twice the speed, suggesting that this could lead to rapid wear if done at high speeds.
  • A similar point is reiterated by another participant, emphasizing the potential issues with locking the differential and recommending a method to lock both sides together instead.
  • A later reply acknowledges the oversight in not considering the implications of locking the differential, expressing appreciation for the clarification provided.

Areas of Agreement / Disagreement

Participants express varying views on the feasibility and implications of the proposed design. While there is agreement on the potential issues with locking the differential, the overall effectiveness and performance impact of the torsion bar idea remains unresolved.

Contextual Notes

Participants highlight limitations regarding the design's assumptions and the potential for wear on differential components, but do not resolve these concerns.

Who May Find This Useful

This discussion may be of interest to individuals exploring electric vehicle design, differential mechanics, and innovative automotive engineering solutions.

Khataro
Messages
2
Reaction score
1
TL;DR
What happens if I have a cv axle on one side of a diff and a torsion bar in the other?
I have a crazy idea to make a 4 motor EV, but ran into an issue: the motors I want to use have a gear reduction (transmission?) That has a differential built into it. I only need to use one side of each, but I don't want to weld or otherwise destroy the other side of it. (That way I can repurpose or sell the parts later on) So now here's my question: if I put a torsion bar into the opposing side of the CV axle, how will that effect power delivery to the wheel? Would it have potential to improve or hinder performance and how?

Thanks in advance for any wisdom. I'm aware that this idea has potential to be brilliant, or amazingly dumb.
 
Engineering news on Phys.org
If you lock one side of a differential, the other side will rotate at twice the speed.

Because vehicles tend to travel in close to straight lines, the pinion gears and their bearings inside the differential are only designed to rotate slowly. I would not recommend locking one side of the differential for any period of time at high speed, since it will wear quickly.

It would be better to lock the two sides of the differential together by preventing pinion rotation inside the carrier.
 
Reply
  • Like
Likes   Reactions: Khataro, jack action and Lnewqban
Baluncore said:
If you lock one side of a differential, the other side will rotate at twice the speed.

Because vehicles tend to travel in close to straight lines, the pinion gears and their bearings inside the differential are only designed to rotate slowly. I would not recommend locking one side of the differential for any period of time at high speed, since it will wear quickly.

It would be better to lock the two sides of the differential together by preventing pinion rotation inside the carrier.
I feel exceptionally shortsighted for not realizing this. Thanks for pointing that out.
 
Reply
  • Like
Likes   Reactions: berkeman
Welcome to PF.
Don't feel bad. The answer is only obvious once you know the answer.

If you know what question to ask, you can probably answer it yourself. Your question was almost perfect.

Working alone is difficult because you need a different brain to review your ideas, or to check your own work. That is what we are here for.
 
Reply
  • Like
Likes   Reactions: fresh_42, berkeman, jrmichler and 2 others

Similar threads

Automotive Mechanism to drive a wheel from an internal motor allowing suspension?
  • · Replies 9 ·
Replies
9
Views
3K
Automotive Electronic Torque Managment in an EV
  • · Replies 7 ·
Replies
7
Views
2K
Building a small electric vehicle
  • · Replies 12 ·
Replies
12
Views
16K