Ribbed Pushrod Shaft for Combustion Engine Valve Train
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Solution Overview
Problem
Existing push rods for internal combustion engine valve trains lack sufficient buckling resistance and flexibility, especially in applications with limited installation space, where conventional designs such as cylindrical or double-conical shapes are inadequate.
Innovation Solution
A push rod with a rib structure on its shaft, which increases buckling resistance and allows for weight reduction and greater flexibility, enabling adaptation to critical space requirements by adjusting the number, size, and placement of ribs, and can be made in one piece with the shank for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cylindrical or double-conical shape is used for the push rod shaft, then the structure is simple and easy to manufacture, but the buckling resistance is insufficient
Solution Approach 1:
The patent applies local quality by adding rib structures only to specific regions of the push rod shaft where buckling resistance is needed, rather than making the entire shaft complex. The ribs are positioned in areas subjected to compressive loads, providing localized reinforcement while keeping other areas simple and easy to manufacture.
Solution Approach 2:
The patent uses a composite structural approach by combining a cylindrical shaft base with added rib structures. This creates a composite geometry that maintains the simplicity of the original cylindrical form while incorporating reinforcing elements that significantly improve buckling resistance without requiring a complete redesign of the shaft.
2Weight of moving object
If the push rod shaft is made with uniform thickness, then manufacturing is simple, but weight cannot be reduced and space flexibility is limited
Solution Approach 1:
The patent implements variable wall thickness through the rib structure, creating local variations in material distribution. The ribs add material only where structural reinforcement is needed for buckling resistance, while other areas maintain thinner walls to reduce overall weight. This localized material optimization maintains manufacturing simplicity while achieving weight reduction.
Solution Approach 2:
The patent changes the wall thickness parameter along the length of the push rod shaft by adding ribs at specific locations. This creates a non-uniform thickness profile that optimizes the balance between weight and structural strength, allowing the shaft to be lighter while maintaining adequate buckling resistance in critical areas.
3Strength
If the push rod has a bulky design to increase buckling resistance, then strength is improved, but the available installation space is reduced
Solution Approach 1:
The patent uses local quality by adding rib structures only to specific segments of the push rod shaft rather than increasing the overall volume. The ribs are positioned in regions where buckling resistance is critical, providing localized reinforcement without requiring a bulky design throughout the entire shaft length. This maintains a compact overall volume suitable for limited installation space.
Solution Approach 2:
The patent addresses the volume-strength contradiction by adding dimensional complexity in the form of radial ribs rather than increasing the longitudinal or radial dimensions of the entire shaft. This adds structural strength through a third dimension (radial ribs extending from the shaft surface) without significantly increasing the overall envelope volume of the push rod.
4Ease of manufacture
If the rib structure is made in separate pieces, then manufacturing flexibility is improved, but assembly complexity and potential instability increase
Solution Approach 1:
The patent applies merging by integrating the rib structures directly into the push rod shaft as a single monolithic component. The ribs are formed as part of the shaft manufacturing process, eliminating the need for separate assembly steps. This ensures structural stability through continuous material bonding while maintaining manufacturing flexibility through integrated design approaches such as casting, forging, or additive manufacturing.
Data Source
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AI summary
The invention relates to a pushrod for a valve train of an internal combustion engine. The invention further relates to a valve train and a motor vehicle, in particular a commercial vehicle, with such a pushrod. The pushrod (1) is characterized in that, to increase its buckling stiffness, a shaft (2) of the pushrod (1) has a ribbed structure (3).