Rolling Four-Bar Linkage Layout for Lighter Tilting Front Ends
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rolling four-bar linkages in tilting motor vehicles are cumbersome, heavy, and costly, negatively impacting the ease of maneuverability and mechanical strength.
Innovation Solution
A modified rolling four-bar linkage with one crosspiece having a shorter half-crosspiece that is not directly hinged to the uprights, reducing weight and cost while maintaining mechanical strength by using a single rigid body connection for the other crosspiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional rolling four-bar linkage is used to ensure mechanical strength and stability, then the vehicle has sufficient structural robustness, but the linkage becomes heavy and cumbersome, negatively affecting ease of maneuverability and increasing cost
Solution Approach 1:
The lower crosspiece is divided into two separate half-crosspieces (front and rear) that are hinged to the uprights, while the upper crosspiece remains as a single rigid body. This segmentation allows the lower crosspiece to be lighter and more flexible, reducing overall weight while maintaining structural strength through the hinge connections to uprights.
Solution Approach 2:
Different parts of the linkage have different structural characteristics: the upper crosspiece is a rigid single body providing overall stability, while the lower crosspiece uses separate hinged half-crosspieces allowing local flexibility and weight reduction. This local differentiation optimizes both strength and weight.
2Strength
If a traditional rolling four-bar linkage with all crosspieces hinged to uprights is used, then the linkage has high mechanical strength, but it increases device complexity and manufacturing cost
Solution Approach 1:
The lower crosspiece is segmented into two hinged half-crosspieces while the upper crosspiece remains unified. This reduces the number of connection points and components needed, simplifying the overall structure while maintaining necessary strength through strategic hinging.
Solution Approach 2:
The hinge connections are extracted from the upper crosspiece and concentrated in the lower crosspiece half-crosspieces. This reduces the number of hinges and connection points in the overall linkage, simplifying manufacturing and assembly while maintaining structural integrity.
3Force
If a heavier four-bar linkage is used to ensure sufficient mechanical strength, then the linkage can bear dynamic loads, but the ease of maneuverability of the vehicle is significantly reduced
Solution Approach 1:
The lower crosspiece is divided into hinged half-crosspieces that can move independently, reducing the overall mass of the linkage. This segmentation allows the linkage to bear necessary loads through distributed hinge connections while reducing the weight that would otherwise hinder maneuverability.
Solution Approach 2:
The hinged half-crosspieces introduce dynamic flexibility to the linkage, allowing it to adapt to road conditions and reduce the force required for steering and maneuvering. The linkage becomes more compliant and easier to move while maintaining load-bearing capacity through the hinge connections.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The tilting motor vehicle comprises a pair of steering front wheels (17A, 17B), linked to the frame (3) of the motor vehicle (1) through a rolling four-bar linkage (21). The rolling four-bar linkage comprises an upper crosspiece (23) and a lower crosspiece (25) linked to each other by uprights (27A, 27B) forming the rocker arms of the four-bar linkage. One of the two crosspieces consists of a front half- crosspiece and a rear half-crosspiece, both hinged to the two uprights. The other half- crosspiece comprises two half-crosspieces, only one of which is hinged at the ends thereof to the two uprights, while the other half-crosspiece is shorter, and it is not hinged to the uprights.