Engine Cover Structure Combining Plastic and Metal for Sealing
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Solution Overview
Problem
Existing cover structures for internal combustion engines face challenges in reducing weight while maintaining sufficient sealing performance, particularly with plastic cover members that are prone to deformation and dimensional inaccuracies, leading to inadequate sealing and increased weight due to the use of metallic holding members.
Innovation Solution
A cover structure combining a plastic cover member with a metallic holding member, where the holding member is positioned to engage with the engine body in both axial and planar directions, and a gasket is sandwiched between the cover member and the holding member to ensure proper sealing, with fastening bolts securing the components together to prevent deformation and enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic cover member is used instead of a metallic cover member, then weight is reduced, but the cover member is easily deformed by heat, pressure, and creep, leading to insufficient sealing performance
Solution Approach 1:
The invention uses a composite structure combining plastic and metal materials. The cover member is made of plastic for weight reduction, while a metal holding member is integrated to provide dimensional stability and prevent deformation. This composite approach allows the structure to benefit from both materials: the lightweight plastic and the deformation-resistant metal, thereby maintaining sealing performance while reducing overall weight.
Solution Approach 2:
The cover structure is divided into separate functional components: a plastic cover member for weight reduction and a metal holding member for structural support and sealing. The holding member is specifically positioned to hold the oil seal and prevent deformation in critical areas, while the cover member provides overall protection. This segmentation allows each component to optimize its material properties for its specific function.
2Weight of moving object
If a plastic cover member is used, then weight is reduced, but it is difficult to meet the required dimension of the oil seal due to deformation in the radial direction
Solution Approach 1:
The invention integrates a metal holding member within the plastic cover member to provide dimensional stability. The metal holding member specifically supports the oil seal, preventing radial deformation and ensuring the required dimensional accuracy. This allows the use of lightweight plastic while maintaining precise dimensions for the oil seal through the reinforcing metal component.
Solution Approach 2:
The metal holding member is strategically positioned only in the critical area where the oil seal is located, providing local reinforcement where dimensional accuracy is most important. The rest of the cover member remains as lightweight plastic, optimizing the overall weight while ensuring precision where needed.
3Reliability
If a metallic holding member is added to prevent deformation, then sealing performance is improved, but the overall weight increases
Solution Approach 1:
The structure is segmented into a lightweight plastic cover member and a localized metal holding member. The metal component is only added where absolutely necessary (at the oil seal location) to prevent deformation, rather than making the entire cover metallic. This segmentation minimizes the amount of heavy metal used while still achieving the sealing performance improvement.
Solution Approach 2:
The metal holding member is applied locally only at the critical sealing area, providing reinforcement exactly where needed to prevent deformation and ensure sealing performance. The rest of the structure remains as lightweight plastic, thereby minimizing weight increase while achieving the desired reliability improvement.
4Stability of the object's composition
If fastening bolts are positioned near the crank shaft to secure the cover member, then deformation is prevented, but the positioning becomes difficult due to centralized components such as sprockets and pulleys
Solution Approach 1:
The fastening function is segmented between the cover member and the holding member. The holding member, which is integrated with the crank shaft area, provides structural support and prevents deformation through its rigid connection. This allows fastening bolts to be positioned more conveniently on the cover member without requiring direct positioning near the crank shaft, thereby easing installation while maintaining deformation resistance.
Solution Approach 2:
The metal holding member acts as an intermediary between the crank shaft area and the cover member. It provides structural support and deformation resistance in the critical crank shaft area, while allowing the cover member to be fastened at more accessible locations. The holding member mediates the structural requirements, enabling easier bolt positioning while maintaining stability.
Data Source
AI summary
A cover structure for an internal combustion engine includes: a plastic cover member attached to a body of the internal combustion engine so as to cover the power transmission and a metallic holding member configured to hold an oil seal pressurized to the outer circumference of the crank shaft. Also, the holding member is positionable by engaging with the body of the internal combustion engine with respect to an axial direction of the crank shaft and a planar direction perpendicular to the axial direction. The cover member and the holding member are fastened together by a fastening bolt while interposing a gasket positioned to surround the crank shaft.