Head Cover Through-Holes for Intermediate Arm Assembly
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Solution Overview
Problem
The assembly of internal combustion engines with intermediate arms for transmitting force from a cam to a rocker arm is hindered by the intermediate arm's tendency to fall or rotate, complicating the mounting of the head cover on the cylinder head due to lack of support.
Innovation Solution
The formation of pair of side through-holes in the head cover to support a rod that secures the intermediate arm, either by penetration or from below, prevents the intermediate arm from falling or rotating, allowing for easier assembly by integrating the head cover and intermediate arm handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the intermediate arm is not supported by a shaft, then the valve actuation mechanism can be simplified, but the intermediate arm may fall before being sandwiched between the cam and the rocker arm during assembly
Solution Approach 1:
The head cover is designed with through-holes that allow the intermediate arm to be preliminarily positioned and held in place before the final assembly step. This preliminary positioning prevents the intermediate arm from falling during assembly while maintaining a simple support structure.
Solution Approach 2:
The through-holes in the head cover act as intermediary structures that temporarily hold the intermediate arm during assembly. These holes provide a mediating mechanism that ensures the intermediate arm stays in position without requiring a complex shaft support structure.
2Stability of the object's composition
If the intermediate arm is rotatably supported by a shaft, then the intermediate arm is stable during assembly, but the intermediate arm is rotated by its own weight before being sandwiched between the cam and the rocker arm
Solution Approach 1:
The through-holes provide preliminary positioning that prevents the intermediate arm from rotating due to its own weight during assembly. By establishing the correct position early in the assembly process, the need for subsequent adjustment operations is eliminated.
Solution Approach 2:
Instead of using a shaft to support the intermediate arm (which causes rotation), the invention inverts the approach by using through-holes in the head cover to constrain the intermediate arm's position. This inverted approach eliminates the rotation problem while maintaining stability.
3Ease of operation
If rocker arms are supported from below by a rod member during assembly, then the rocker arms do not rotate individually, but the assembly process requires additional components and steps
Solution Approach 1:
The support function is merged into the head cover structure itself through the provision of through-holes. Instead of using a separate rod member to support the intermediate arm, the head cover's own structure provides the support, eliminating the need for additional components.
Solution Approach 2:
The head cover serves its own support function by incorporating through-holes that automatically hold the intermediate arm in position during assembly. This self-service approach eliminates the need for external support structures and simplifies the assembly process.
Data Source
AI summary
An internal combustion engine includes: a head cover covering a cylinder head; and a variable valve actuation mechanism. The variable valve actuation mechanism includes: a cam placed inside the head cover and rotating with a camshaft extending in a rotation axis direction; and an intermediate arm placed inside the head cover and sandwiched between the cam and a rocker arm. A pair of side through-holes, which are provided for a support rod supporting the intermediate arm to pass through, are formed in side portions of the head cover so as to face each other along the rotation axis direction.