Pivot Foot Motion Restriction in Dual Body Rocker Arms
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Solution Overview
Problem
Internal combustion engines face challenges in integrating rocker arms with the valve train, particularly in restricting the motion of pivot feet to ensure proper alignment and operation of valve tips without manual adjustment.
Innovation Solution
A dual body rocker arm design featuring an outer arm, inner arm, cylindrical pivot axle, pivot foot, and retaining rings with interfering protrusions, which allow partial rotation of the pivot foot and restrict its motion to maintain alignment with the valve tip, and an alternative embodiment with interfering blocks for motion restriction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pivot foot is allowed to rotate freely about the axle, then the assembly is easy to manufacture and install, but the valve tip experiences excessive side-to-side movement and misalignment
Solution Approach 1:
The pivot foot is designed to rotate dynamically about the axle during assembly, allowing easy installation, while the interfering protrusions and projections create dynamic constraints that limit the rotation range to prevent excessive valve tip movement during operation
Solution Approach 2:
The interfering protrusions and projections act as intermediary elements between the pivot foot and the arm, mediating the rotational motion to allow partial rotation for assembly while preventing excessive movement during operation
2Manufacturing precision
If the pivot foot motion is restricted using interfering protrusions and projections, then the valve tip alignment is improved, but the device complexity increases
Solution Approach 1:
The motion restriction mechanism is segmented into discrete interfering protrusions and projections located at specific positions on the pivot foot and arm, allowing precise control of rotational range without requiring complex continuous constraint mechanisms
Solution Approach 2:
The interfering features are positioned locally at specific locations on the pivot foot and arm where they provide the necessary motion restriction, rather than requiring comprehensive complex constraints throughout the entire structure
Data Source
AI summary
A dual body rocker arm comprising an outer arm, an inner arm, a substantially cylindrical pivot axle, a pivot foot and a first and second pivot foot retaining ring. The inner arm is disposed between side arms of the outer arm. The pivot axle is mounted to both the inner and outer arm. The pivot foot has a cylindrical axle interfacing surface and a valve tip interface. Retaining rings mount the pivot foot to the axle, allowing partial rotation of the pivot foot about the axle. Interfering protrusions on the retaining rings limit the range of motion of the pivot foot. A pivot foot having at least one interfering block is configured to restrict motion of the pivot foot by interfering with at least one interfering tab.