Variable Valve Device Rocker Arm Layout for Engine Compactness
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Solution Overview
Problem
Existing variable valve devices increase engine size and hinder component commonality due to the placement of a spring pin, making it difficult to accommodate a cam chain and spark plug in a multi-cylinder engine.
Innovation Solution
A variable valve device design featuring a rocker shaft, swingable rocker arms, a connecting pin, a return pin, a pressing member, and a repulsive member, where the connecting pin, return pin, and repulsive member are arranged in a space separated from the spark plug, allowing for improved component layout freedom and preventing engine size increase, while enabling the use of the same rocker arm for multiple cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring pin is disposed in the pin hole of the rocker arm to push back the connecting pin, then the connecting pin can be pushed back to release the connection, but the size of the engine increases
Solution Approach 1:
The patent combines the spring pin and return pin functions into a single integrated return pin structure. The return pin has a first end that contacts the connecting pin and a second end that is elastically deformable, eliminating the need for a separate spring pin while achieving the same push-back function to release the connection between rocker arms.
Solution Approach 2:
The return pin serves multiple functions: it acts as both the elastic element (replacing the spring pin) and the push-back mechanism. The elastically deformable second end provides the pushing force, while the first end transmits this force to the connecting pin, achieving multi-functionality with a single component.
2Ease of operation
If a spring pin is disposed in the rocker arm to enable connection release, then the connecting pin can be pushed back, but component commonality cannot be achieved
Solution Approach 1:
The return pin with its elastically deformable second end and first end for contacting the connecting pin provides a universal solution that can be applied to different rocker arm configurations. This integrated design allows the same rocker arm design to be used across multiple cylinders with cam chains interposed, achieving component commonality while maintaining the push-back function.
3Ease of operation
If the connecting pin is pushed into the pin hole of the other rocker arm to connect rocker arms, then simultaneous valve operation is achieved, but the space between cam chain and spark plug is insufficient
Solution Approach 1:
The connecting pin is received within the pin hole of the other rocker arm, with the pin hole providing a recess that accommodates the connecting pin. This nested arrangement allows the connecting pin to be pushed into the pin hole to connect the rocker arms for simultaneous valve operation without requiring additional external space, fitting compactly within the existing rocker arm structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design prevents engine size increase and achieves component commonality by allowing the same rocker arm to be used across cylinders, enhancing the flexibility of component layout and reducing costs.
Implementation Method 1
a repulsive member configured to cause the return pin to push back the connecting pin to one side
Data Source
AI summary
A variable valve device can change valve operations of a cylinder head in which a cam chain is disposed at a center in a predetermined direction where cylinders are arranged and spark plugs are arranged by recessing outer walls on both sides in the direction in a concave shape. The device includes, for each cylinder, a rocker shaft extending along the direction, rocker arms supported by the rocker shaft, a connecting pin disposed in a pin hole of one of the rocker arms, a return pin disposed in a pin hole of the other of the rocker arms, a pressing member that causes the connecting pin to push the return pin, and a repulsive member that causes the return pin to push back the connecting pin, and the pins and the members are separated from the plug in a direction orthogonal to the direction in a plan view.