Resinous Cap Grommet Fixing for Outboard Motor Water Sealing
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Solution Overview
Problem
The existing cable insertion structures for outboard motors, which use rubber grommets to prevent water ingress, fail to securely attach the grommet to the casing, leading to potential water immersion when external forces are applied, causing the grommet to come off the through hole.
Innovation Solution
A resinous cap is used to fix the rubber grommet to the outer casing of the outboard motor, featuring a communicating section, inner and outer collar sections, a pressing section, a supporting section with an ellipse-shaped profile, and a pawl section that sandwiches the grommet, ensuring it remains attached even under external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rubber grommet is simply fitted to the through hole, then the structure is simple and easy to manufacture, but the rubber grommet may come off the through hole by external force that pulls the cable, causing water to enter
Solution Approach 1:
The resinous cap is inserted into the communicating hole of the rubber grommet, creating a nested structure where the cap is housed within the grommet. This nesting arrangement secures the grommet to the outer casing, preventing it from being pulled off by external forces while maintaining a relatively simple overall structure.
Solution Approach 2:
The resinous cap acts as an intermediary component between the rubber grommet and the outer casing. It mediates the connection by being inserted into the grommet's communicating hole, providing a secure attachment mechanism that prevents the grommet from dislodging under external forces.
2Device complexity
If the rubber grommet is fitted without additional fixing components, then the device complexity is low, but the grommet cannot resist external pulling forces on the cable
Solution Approach 1:
The resinous cap is inserted into the communicating hole of the rubber grommet, creating a nested structure where the cap is housed within the grommet. This nesting arrangement secures the grommet to the outer casing, preventing it from being pulled off by external forces while maintaining a relatively simple overall structure.
Solution Approach 2:
The solution moves from a simple surface-level fitting (grommet on outer casing) to a three-dimensional insertion (cap into grommet's communicating hole). This dimensional change provides mechanical interlocking that resists pulling forces without significantly increasing structural complexity.
3Ease of operation
If a through hole is formed in the cowling for cable insertion, then cable access is enabled, but water can enter from the clearance between the through hole and cable
Solution Approach 1:
The rubber grommet provides localized sealing quality at the through hole where the cable passes through. The grommet's material properties (elasticity, water resistance) are specifically applied at this critical location to prevent water ingress while allowing cable passage.
Solution Approach 2:
The rubber grommet acts as a flexible sealing element that can deform to accommodate the cable while maintaining a tight seal around it. This flexibility allows the grommet to conform to the cable shape and prevent water from entering through the clearance between the through hole and cable.
Data Source
AI summary
In a cable insertion structure for an outboard motor, a pawl section and a supporting section of a resinous cap are inserted from the inside of a cowling into a communicating hole of a rubber grommet, and the pawl section is fitted into a recess. Then, the communicating section of the rubber grommet is sandwiched between the pawl section and the pressing section, and thus the resinous cap is fixed to the rubber grommet. In the above-described state, a cable is inserted from an insertion hole of the resinous cap into a cable housing section of the rubber grommet. A clip band is fastened to a groove of the cable housing section to fix the cable housing section to the cable. The cable insertion structure for an outboard motor prevents a rubber grommet from coming off even when an external force that pulls the cable is applied.