CVT Waterproof Case Sealing Structure for Rough-Terrain Water Tightness
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Solution Overview
Problem
Existing waterproof cases for continuously variable transmissions (CVT) face challenges in maintaining effective water sealing, particularly under conditions where the CVT is exposed to rough terrain or water, due to the limitations of traditional sealing mechanisms.
Innovation Solution
A waterproof case design featuring a sealing member interposed between the case main body and cover, with a circumferential projection that projects from the contact surface and includes tapered sections to ensure uniform pressing force on the sealing member, enhancing the water-tightness by inclining the fastener axis and contact surfaces to obviate bending stresses and prevent water intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional sealing mechanism is used in the waterproof case, then the structure is simple, but the water-tightness is insufficient under rough terrain conditions
Solution Approach 1:
The sealing member is designed with non-uniform thickness, being thicker at the circumferential projection area and thinner at other areas. This local quality variation allows the sealing member to concentrate pressing force where it is most needed (at the circumferential projection) while maintaining overall sealing effectiveness, thereby improving water-tightness without requiring a completely complex sealing structure
Solution Approach 2:
The contact surface between the case main body and cover is designed with a curved surface rather than a flat surface. The circumferential projection features tapered sections with specific inclination angles (30-60 degrees). This curvature and inclination design distributes the pressing force more effectively across the sealing member, improving sealing performance under rough terrain conditions while maintaining structural simplicity
2Reliability
If the cover is tightly fastened to ensure water sealing, then the water-tightness improves, but the assembly and disassembly becomes difficult
Solution Approach 1:
The fastening mechanism incorporates threaded fasteners that allow for adjustable tightening. The circumferential projection with tapered sections (inclination angles of 30-60 degrees) creates a dynamic pressing force distribution that automatically adapts to sealing requirements. This dynamic design ensures adequate water-tightness while allowing the cover to be attached and detached through standard threading operations
Solution Approach 2:
The inclination angles of the tapered sections on the circumferential projection are specifically designed within the range of 30-60 degrees. This parameter optimization ensures that the pressing force is sufficient to maintain water-tightness during operation, while the threaded fastener geometry allows for easy assembly and disassembly by changing the fastening torque parameter
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
The design improves the water-tightness of the CVT case, preventing water ingress even when the vehicle traverses rough terrain, thus enhancing the off-road performance by maintaining the integrity of the CVT mechanism.
Implementation Method 1
a circumferential projection that projects from the contact surface in the die pull-out direction, is arranged circumferentially along the contact surface, and presses the sealing member
Implementation Method 2
The circumferential projection includes an outer peripheral side surface and an inner peripheral side surface. In the first region, the circumferential projection has a tapered section in which the outer peripheral side surface is inclined relative to the die pull-out direction. In the second region, the circumferential projection has a tapered section in which the inner peripheral side surface is inclined relative to the die pull-out direction.
Implementation Method 3
a sealing member interposed between the case main body and the cover
Data Source
AI summary
In a waterproof case, a contact surface of a specific member that is a case main body or a cover is a surface extending along a predetermined oblique direction inclined relative to a perpendicular plane orthogonal to a die pull-out direction. The specific member includes a circumferential projection that projects from the contact surface in the die pull-out direction, is arranged circumferentially along the contact surface, and presses a sealing member. The circumferential projection includes an outer peripheral side surface and an inner peripheral side surface. In the first region, the circumferential projection has a tapered section in which the outer peripheral side surface is inclined relative to the die pull-out direction. In the second region, the circumferential projection has a tapered section in which the inner peripheral side surface is inclined relative to the die pull-out direction.