Divided Wishbone Suspension for High Steering Angles

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Solution Overview

Problem

Conventional wheel suspensions, such as McPherson and Revo-Knuckle, limit steering angles to around 45° due to constant velocity joints, leading to reduced maneuverability and increased energy consumption when attempting to turn wheels, especially in driven wheels, which can result in wheels being pushed off the road.

Innovation Solution

A wishbone suspension system with two pivotable partial wishbones, each connected to both the wheel and vehicle connection joints, allowing for increased steering angles up to 90° or more by spacing part of the wishbone from the pivot axis, enabling improved maneuverability and reducing the need for complex and energy-intensive actuation systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional wheel suspensions with constant velocity joints are used, then the suspension structure is simple and reliable, but the maximum steering angle is limited to around 45°

Engineering Contradiction:
Improvesteering angleVSAvoidsuspension structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The wishbone is divided into two separate pivotable partial wishbones (first and second partial wishbones), each capable of independent pivoting about its own pivot axis. This segmentation allows each partial wishbone to clear the wheel during steering, enabling steering angles up to 90° or more while maintaining a relatively simple suspension structure without complex actuation systems

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the steering angle is increased beyond 45° in driven wheels, then maneuverability improves, but the constant velocity joint experiences excessive deflection angles causing wheel push-off

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidjoint performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The partial wishbones are designed to be pivotable about their respective pivot axes, allowing them to dynamically adjust their positions during steering. This dynamic movement enables the partial wishbones to clear the wheel and maintain proper joint angles, preventing excessive deflection and wheel push-off while achieving high steering angles for improved maneuverability

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If electric actuators with gears and control modules are used to achieve strong turning, then steering capability improves, but device complexity, cost, weight, and energy consumption increase

Engineering Contradiction:
Improvesteering capabilityVSAvoidactuation system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pivotable partial wishbones utilize the wheel's own steering movement to automatically clear the wheel and achieve high steering angles without requiring external actuation systems. The suspension geometry itself provides the steering capability, eliminating the need for electric actuators, gears, and control modules, thereby reducing device complexity, cost, weight, and energy consumption while maintaining strong steering capability

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2822786B1Compound suspension arm with separate swivelling arms
Publication Date: 2018.08.01 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2822786B1 patent drawingFigure 1~4
  • EP2822786B1 patent drawingFigure 5~9
  • EP2822786B1 patent drawingFigure 10~15

AI summary

The invention relates to a divided transverse link (20) for a wheel (10) of a vehicle, said transverse link comprising at least one wheel connection joint (21a, 21b, 21c) for the articulated connection of the transverse link (20) to the wheel (10), at least two vehicle connection joints (22, 23) for the articulated connection of the transverse link (20) to the vehicle, and at least two component transverse links (24, 25), wherein the component transverse links (24, 25) are connected at one side to a vehicle connection joint (22, 23) and at the other side to a wheel connection joint (21a, 21b, 21c). To improve the manoeuvrability of the vehicle, at least one of the component transverse links (24, 25) is pivotable about a pivot axis (V24, V25) which extends between the wheel connection joint (21a, 21b, 21c) and the vehicle connection joint (22, 23) of the component transverse link (24, 25), wherein at least one part of the pivotable component transverse link (24, 25) is formed so as to be spaced apart from the pivot axis (V24, V25) of the pivotable component transverse link (24, 25). The invention also relates to a wheel suspension equipped therewith, and to a motor vehicle.