Trailer Axle Toe Angles for Wide Base Tire Wear Control
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Solution Overview
Problem
Wide base tires on tractor trailers experience irregular wear, leading to premature tire removal due to uneven tread wear, despite modifications aimed at reducing this issue.
Innovation Solution
The use of forward and rearward axles with angled mounting portions relative to the lateral direction, which angles the wide base tires to promote even wear and reduce irregular wear patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wide base tires are used instead of dual tires, then fuel consumption is reduced and weight is reduced, but irregular wear occurs leading to premature tire removal
Solution Approach 1:
The patent applies asymmetry by angling the mounting portions of the axle at specific degrees (e.g., 5 degrees) relative to the vertical axis. This asymmetric mounting configuration changes the tire contact patch distribution and wear pattern, converting the harmful symmetric wear into a controlled asymmetric pattern that extends tire life while maintaining the fuel efficiency benefits of wide base tires
2Weight of moving object
If wide base tires are used instead of dual tires, then overall weight is reduced, but irregular wear occurs leading to premature tire removal
Solution Approach 1:
The asymmetric mounting portion angle creates a controlled wear pattern that distributes stress more evenly across the tire tread, preventing the irregular wear that would otherwise cause premature removal of the lightweight wide base tires
3Duration of action of moving object
If mounting portions are angled relative to lateral direction, then irregular wear is reduced and tire life is extended, but axle structure becomes more complex
Solution Approach 1:
The patent changes the geometric parameter of the mounting portion angle from the conventional vertical alignment to a specific angled configuration (e.g., 5 degrees). This parameter change achieves improved wear distribution and extended tire life while maintaining relatively simple axle construction, as it involves only a modification of the mounting angle rather than a complete structural redesign
Data Source
AI summary
An apparatus (10) is provided, configured for use with a trailer (48) of a tractor trailer (44), that includes forward and rearward axles (12, 28) that each have a central body. The forward axle (12) has first and second mounting portions (16, 20) that are configured to receive first and second wide base tires (24, 26). The rearward axle (28) has first and second rearward mounting portions (32, 36) configured to receive third and fourth wide base tires (40, 42). The first forward mounting portion axis (18) is oriented at an angle (56) from +0.75-+0.95 degrees to the lateral direction, and the second forward mounting portion axis (22) is oriented at an angle (58) from +0.08-+0.28 degrees to the lateral direction. The first rearward mounting portion axis (34) is oriented at an angle (60) from +0.65-+0.85 degrees to the lateral direction, and the second rearward mounting portion axis (38) is oriented at an angle (62) from −0.05-+0.15 degrees to the lateral direction.