Steered Rear Axle Linkage for Lower Joint Stress and Packaging
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Solution Overview
Problem
The existing rear axle designs with steered wheels face challenges in manufacturing complexity and transverse force filtration due to limited space and increased stress on joints, particularly at the front joint of the longitudinal arm during cornering.
Innovation Solution
A rear axle design featuring a longitudinal arm with a transverse axis articulation mounted on the chassis, a steering knuckle, and a connecting structure comprising a transverse lower and upper arm, where the lower arm's third articulation connects directly to the steering knuckle, separating guiding and suspension functions, and optimizing the pivot axis position to reduce forces on the steering rod and actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional rear axle design with longitudinal arm and parallelogram connection is used, then the wheel steering function is achieved, but the manufacturing complexity increases and the articulation is subjected to high transverse forces
Solution Approach 1:
The patent divides the lower arm into two separate arms: a guiding arm that handles transverse forces and a supporting arm that handles vertical suspension forces. This segmentation allows each arm to be optimized for its specific function, reducing the stress on any single articulation point and simplifying the overall manufacturing process.
Solution Approach 2:
The patent introduces a trailing arm as an intermediary component that connects the steering knuckle to the chassis. This trailing arm acts as a mediator that filters transverse forces during cornering, reducing the stress on the longitudinal arm's articulation points and simplifying the design of other components.
2Ease of operation
If the longitudinal arm is subjected to transverse forces during cornering, then the wheel steering is maintained, but the articulation requires more space to filter these forces
Solution Approach 1:
The trailing arm serves as an intermediary component that specifically handles the filtration of transverse forces during cornering. By assigning this function to the trailing arm, the longitudinal arm and its articulations are relieved of the need to accommodate large spaces for force filtration, thus reducing the overall space required in the articulation area while maintaining full wheel steering capability.
3Device complexity
If the lower arm is directly connected to the steering knuckle at both ends, then the structure is simplified, but the guidance and suspension functions cannot be separated
Solution Approach 1:
The lower arm is segmented into two distinct components: the guiding arm (connecting to the upper end of the steering knuckle) and the supporting arm (connecting to the lower end of the steering knuckle). This segmentation enables the guiding arm to specialize in handling transverse guidance forces while the supporting arm handles vertical suspension forces, achieving functional separation without excessive structural complexity.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a rear axle (1) for a motor vehicle comprising at least one longitudinal arm (5) whose front end is articulated on a chassis (4) of the vehicle, at least one wheel carrier (3) and an associated rear wheel, and a connecting structure comprising a lower transverse arm (6) and an upper transverse arm (7). Each arm has a first joint (61, 71) connecting it to the wheel carrier (3) and a second joint (62, 72) connecting it to the chassis. The rear end (52) of the longitudinal arm is pivotally mounted on a front end (31) of the wheel carrier. Furthermore, the first joint (61) of the lower arm is connected to an upper end (32) of the wheel carrier by a connecting rod (8), and the lower arm (6) is connected to a lower end (33) of the wheel carrier by a third joint (63) located forward of a line defined by its first and second joints (61, 62).