Engine Valve Bush Mounting for Deformation Control
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Solution Overview
Problem
Conventional opening/closing valves for engine intake and exhaust passages face issues with deformation due to heat or pressure, leading to unreliable smooth operation, particularly in systems where dimensional precision is compromised by resin molding and thermal expansion.
Innovation Solution
The design incorporates a valve body with butterfly valves and shaft portions connected by bush members and a shaft member, where the bush members are mounted to project from the valve body, allowing for relative rotation disablement, thereby reducing deformation and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If butterfly valves and shaft portions are integrally molded of resin, then manufacturing complexity is reduced, but deformation occurs due to heat or pressure application
Solution Approach 1:
The valve body is divided into multiple independent resin-molded valve elements (first valve element, second valve element, third valve element) that are assembled together using connecting members. This segmentation allows each element to be manufactured separately with controlled deformation, while the overall structure maintains reliability through the modular assembly approach.
Solution Approach 2:
Connecting members (such as shaft portions) serve as intermediaries between the resin-molded valve elements. These connecting members are designed to accommodate thermal expansion and pressure-induced deformation of the resin components, thereby preventing direct stress transmission that would cause deformation while maintaining the integral molding advantage.
2Ease of operation
If shaft portions are made longer to connect butterfly valves, then ease of operation is improved, but sliding resistance increases due to warp or deflection
Solution Approach 1:
The connecting members are designed with dynamic characteristics that allow them to flex and adapt to thermal expansion and pressure conditions. The shaft portions incorporate features such as tapered shapes or flexible joints that enable smooth rotation while accommodating dimensional changes, thereby maintaining ease of operation without excessive sliding resistance.
3Reliability
If bush members are mounted to project from valve body, then deformation is suppressed, but device complexity increases
Solution Approach 1:
The bush members are integrated with the connecting members in a unified structure. The connecting members serve dual functions as both structural connectors and rotational support elements, eliminating the need for separate mounting structures and reducing overall device complexity while maintaining the deformation suppression benefits of the projected bush member configuration.
Data Source
AI summary
An opening/closing valve structure for an engine is provided with a valve body for opening and closing an intake passage or an exhaust passage of the engine; a pair of bush members mounted on axial ends of the valve body; and a shaft member axially passing through one of the bush members and projecting from the bush member by a predetermined length within one end of the valve body. Each of the bush members is mounted in such a manner that a part of the bush member is axially received in an end of the valve body and the remaining part thereof axially projects from the end of the valve body. A portion of the shaft member projecting from the one of the bush members is connected to the valve body in such a manner that relative rotation of the shaft member with respect to the valve body is disabled.