Rear Suspension Toe Angle Control via Trailing Arm Geometry
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Solution Overview
Problem
Existing vehicle rear suspension systems tend to change the toe angle of the rear wheel in a toe-out direction during braking, which can lead to instability and poor handling.
Innovation Solution
A vehicle rear suspension system is designed with a trailing arm and lateral arm configuration where the angle between the trailing arm and lateral arm is 90 degrees or greater, with the third coupling point located near the rearmost part of the vehicle body, and includes a toe-control link to reduce toe angle changes during braking and over bumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rear wheel is fastened to the trailing arm with a bolt to fix the angle, then the angle between the rear wheel and trailing arm is fixed, but the toe angle changes in a toe-out direction during braking
Solution Approach 1:
The patent changes the geometric parameters of the suspension system by positioning the lateral arm coupling point at a specific location on the trailing arm and configuring the lateral arm at a specific angle relative to the trailing arm. This geometric parameter optimization ensures that during braking, the force transmission through the lateral arm creates a moment that counteracts the toe-out tendency, thereby controlling the toe angle to change in a toe-in direction or minimize toe-out change.
2Strength
If two parallel lateral arms are arranged bridging the space between the rear end of the trailing arm and the vehicle frame, then the structure provides support, but the toe angle changes in a toe-out direction when braking force acts on the rear wheel
Solution Approach 1:
The patent introduces asymmetry in the lateral arm configuration by positioning the coupling point between the lateral arm and trailing arm at a specific offset distance from the trailing arm's rear end, rather than using symmetric parallel arms. The lateral arm is also configured at a specific angle relative to the trailing arm, creating an asymmetric geometric relationship that optimizes the force transmission path during braking to control toe angle behavior.
Data Source
AI summary
A vehicle that can reduce change in the toe angle of a rear wheel in a toe-out direction at the time of a braking force being provided by the vehicle. A coupling point between a vehicle frame and a trailing arm is defined as a first coupling point. A coupling point between the trailing arm and a lateral arm is defined as a second coupling point. A coupling point between the lateral arm and a frame rear section is defined as a third coupling point. A straight line connecting the first coupling point and the second coupling point is defined as a first straight line. A straight line connecting the second coupling point and the third coupling point is defined as a second straight line. With those definitions, an angle between the first straight line and the second straight line in a plan view of the vehicle is 90 degrees or greater.