Steerable Wheel Suspension for Large Steering Angles
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Solution Overview
Problem
Existing suspension systems fail to maximize wheel steering angles while avoiding large reaction torques and increased unsprung masses, which are critical for enhancing maneuverability and ride comfort in confined spaces.
Innovation Solution
A suspension system with a first and second body, an actuator, and multiple linkage elements that allow for a maximum wheel steering angle of ±70° by rotating the second body about a vertical axis, transferring this motion to the first body through coordinated linkage elements, reducing unsprung mass by distributing torque and force support across multiple bearing points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wheel steering angles are maximized to enhance maneuverability, then vehicle maneuverability is improved, but large reaction torques are generated at the bearing point
Solution Approach 1:
The suspension is divided into two separate bodies (first body and second body) that are rotatably connected. The first body is attached to the vehicle body at a first bearing point, while the second body is attached at a second bearing point. This segmentation allows the steering actuator to rotate the second body, which in turn rotates the first body and steers the wheel, thereby distributing and reducing the reaction torque at each bearing point while achieving large wheel steering angles.
Solution Approach 2:
The second body acts as an intermediary between the vehicle body and the first body (wheel carrier). The steering actuator rotates the second body, which then transfers this rotation to the first body through the rotatable connection. This intermediary mechanism enables the system to achieve large wheel steering angles while distributing the reaction forces across multiple bearing points, reducing the torque burden on any single point.
2Ease of operation
If steering actuator is attached to knuckle to enable individual wheel steering, then wheel steering control is achieved, but unsprung mass increases
Solution Approach 1:
The suspension system is segmented into two bodies: the first body (wheel carrier) and the second body (steering carrier). The steering actuator is mounted on the vehicle body and connects to the second body, which is rotatably connected to the first body. This segmentation allows the steering actuator to control wheel steering without being part of the unsprung mass, as the actuator remains supported by the vehicle body through the two-body linkage system.
Solution Approach 2:
The second body serves as an intermediary that transfers the steering action from the actuator to the wheel carrier (first body). By positioning the actuator on the vehicle body and using the second body as a mediator, the system achieves individual wheel steering control while keeping the actuator mass supported by the sprung mass (vehicle body), thereby avoiding an increase in unsprung mass.
3Ease of operation
If space constraints from conventional suspensions are eliminated to achieve larger steering angles, then wheel steering angle range is improved, but device complexity increases
Solution Approach 1:
The suspension is segmented into two rotatable bodies connected by a rotatable connection. The first body is attached to the vehicle body via a first bearing point, and the second body is attached via a second bearing point. This segmentation eliminates the need for conventional space-consuming components like tie rods, allowing for larger wheel steering angles while maintaining a relatively simple and compact structure.
Solution Approach 2:
The patent introduces a vertical dimension to the steering mechanism by allowing the second body to rotate about a second rotation axis that extends in the vertical direction. This dimensional change enables the steering actuator to achieve large wheel steering angles without requiring extensive lateral space, thereby reducing the overall device complexity while maximizing the steering angle range.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
A suspension for a vehicle comprises a first body to which a wheel of the vehicle can be rotatably attached and a second body rotatably attachable to a vehicle body of the vehicle. The second body is rotatable about a second rotation axis. The suspension further comprises an actuator, operatively coupled to the second body, for driving rotation of the second body about the second rotation axis. The suspension further comprises at least a first linkage element and a second linkage element. The first linkage element is movably attached to the first body and to the second body and the second linkage element is movably attached to the first body and to the second body. The first linkage element and the second linkage element commonly enable rotation of the first body about a first rotation axis in response to a rotation of the second body about the second rotation axis. The suspension further comprises a third linkage element movably attached to the first body and to the vehicle body.