Variable Valve Mechanism Swinging Arm Abrasion Reduction
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Solution Overview
Problem
Existing variable valve mechanisms experience significant displacement of the swinging arm relative to the valve when changing lift characteristics, leading to potential abrasion and inefficiencies.
Innovation Solution
A variable valve mechanism that includes a swinging arm, a regulating member, and a connection member, where the regulating member restricts the displacement of the swinging arm's first end portion relative to the valve, and the connection member allows controlled movement of the second end portion via a moving device, using an engaging pin and insertion hole configuration to minimize contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control cam is rotated to change lift characteristics, then the valve timing and lift amount change, but the tip portion of the swinging arm displaces relative to the valve causing abrasion
Solution Approach 1:
A cap is introduced as an intermediary component between the swinging arm and the valve. The cap includes a contact surface that receives the tip portion of the swinging arm, allowing the swinging arm to move while the cap remains stationary relative to the valve. This mediator absorbs the displacement and prevents direct abrasion between the swinging arm and valve.
Solution Approach 2:
The contact surface of the cap is designed with a curved surface extending in the valve axis direction, allowing the swinging arm to move in a direction that is not parallel to the valve axis. This dimensional change enables the swinging arm to follow a curved path, reducing displacement and abrasion while still achieving the desired valve timing and lift amount changes.
2Object-affected harmful factors
If the tip portion of the swinging arm is constrained to reduce displacement, then abrasion is reduced, but the mechanism complexity increases
Solution Approach 1:
The cap serves multiple functions: it provides a contact surface for the swinging arm, acts as a bearing surface to reduce friction, guides the movement of the swinging arm tip, and protects the valve from direct contact. By making the cap multi-functional, the solution reduces abrasion without significantly increasing overall mechanism complexity.
Data Source
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Figure 3A~3B
AI summary
A variable valve mechanism includes: a cam that rotates about a rotating shaft in association with rotation of a crank shaft of an engine; a swinging arm that is disposed between the cam and a valve and is pushed by the rotating cam to swing and push the valve by a first end portion of the swinging arm; a moving device that moves a second end portion of the swinging arm; a regulating member that is coupled to the first end portion of the swinging arm so as to be rotatable about a swinging shaft parallel to the rotating shaft and regulates displacement of the first end portion of the swinging arm relative to the valve when the second end portion of the swinging arm is moved by the moving device; and a connection member that connects the second end portion of the swinging arm to the moving device such that when the second end portion of the swinging arm is moved by the moving device, movement of the second end portion of the swinging arm about the swinging shaft is allowed.