Box-Type Piston Ring Support Structure for Weld Seam Stress
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Solution Overview
Problem
Box-type pistons experience significant deformation and stress due to bending moments during engine operation, particularly at the transitions between box walls and skirt walls, leading to potential weld seam failure and reduced component safety.
Innovation Solution
Incorporating tetrahedron-shaped or trapezoidal support elements that extend over the entire radial width of the free-standing underside of the ring section, connecting it to the box walls, effectively reducing deformation and stress on the weld seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ring section is made free-standing with overhanging underside to reduce weight and simplify structure, then manufacturing complexity is reduced, but deformation and stress under gas pressure increase significantly
Solution Approach 1:
The support elements divide the ring section into multiple supported zones, with each segment backed by its own support element. This segmentation allows the ring section to maintain a free-standing design while distributing the load across multiple discrete support points, reducing both deformation and stress concentration.
Solution Approach 2:
The support elements are integrally formed with the piston body, creating a composite structure where the ring section, support elements, and piston body form a unified load-bearing system. This integral construction optimizes stress distribution while maintaining structural simplicity.
2Reliability
If support elements are added to reduce ring section deformation, then component reliability improves, but piston weight increases
Solution Approach 1:
Support elements are strategically positioned only at critical locations where the ring section transitions to the piston body, rather than providing continuous support. This localized approach provides maximum structural benefit at the weld seam regions while minimizing additional weight throughout the entire piston.
Solution Approach 2:
The support elements extend partially into the ring section depth, providing sufficient support to reduce deformation and protect weld seams without requiring full-depth support that would increase weight unnecessarily. The partial extension achieves the critical function of stress reduction with minimal material addition.
3Stability of the object's composition
If the ring section is reinforced to reduce deformation, then structural stability improves, but manufacturing complexity and weight increase
Solution Approach 1:
The support elements act as intermediary structures between the ring section and the piston body, providing mechanical support without requiring direct reinforcement of the ring section itself. This intermediary approach achieves rigidity enhancement while keeping the ring section design simple and manufacturable.
Data Source
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AI summary
The present invention relates to a piston (10) for an internal combustion engine, comprising a piston crown (13), a circumferential fire land (14), a circumferential ring part (15) having annular grooves, and a piston skirt (16), which comprises two skirt walls (17) and two box walls (18) set back from the ring part (15) and connecting the skirt walls (17) in such a way that an exposed underside (25) of the ring part (15) is formed in the area of each of the box walls (18), wherein the box walls (18) are provided with pin bosses (19) having pin bores (21). According to the invention, at least one support element (26a, 26b) is arranged between each exposed underside (25) of the ring part (15) and the box wall (18) associated with said underside of the ring part.