Lawn Mower Waterproofing via Peripheral Surface Step
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Solution Overview
Problem
Existing lawn mowers face challenges in maintaining waterproofness, particularly when high-pressure cleaning is used, leading to increased complexity and cost in waterproofing solutions.
Innovation Solution
A simple waterproofing arrangement featuring a flat annular frame-side seal surface and an annular lawn mowing unit peripheral surface with a step boundary, combined with a double seal structure involving a housing-side seal surface, to redirect and weaken cleaning water pressure, preventing it from entering the sealed portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a waterproof device is formed to prevent cleaning water from entering the interior, then waterproofness is improved, but the waterproof structure becomes complicated and cost increases
Solution Approach 1:
The lawn mowing unit itself serves as a barrier to cleaning water through its peripheral surface configuration. The unit's own structure (peripheral surface extending from the seal surface to the outer edge) creates a self-contained water deflection system that protects the mounting portion without requiring additional waterproofing components
Solution Approach 2:
The solution moves from a vertical sealing approach (sealing the mounting portion from above) to a horizontal dimension approach (extending the lawn mowing unit peripheral surface horizontally from the seal surface to the outer edge). This dimensional shift creates a water-deflecting barrier that naturally redirects cleaning water away from the sealed interior
2Reliability
If a waterproof device is formed to prevent cleaning water from entering the interior, then waterproofness is improved, but cost increases
Solution Approach 1:
The lawn mowing unit is given a dual function: it performs its primary cutting function while simultaneously serving as a water-deflecting barrier through its peripheral surface configuration. This multi-functionality eliminates the need for separate waterproofing components, reducing overall manufacturing cost
Solution Approach 2:
The waterproofing function is merged with the existing lawn mowing unit structure. The peripheral surface of the lawn mowing unit is configured to extend from the seal surface to the outer edge, combining the cutting mechanism and water protection function into a single integrated component
3Ease of operation
If high-pressure cleaning water is sprayed against the lower portion, then cleaning effectiveness is improved, but water pressure can force water into sealed portions
Solution Approach 1:
The high-pressure water spray, which could potentially harm the sealing by forcing water into sealed portions, is converted into a beneficial force. The lawn mowing unit peripheral surface acts as a water deflector that redirects the high-pressure spray away from the seal surface, using the water's own momentum against the sealing area
Data Source
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AI summary
A lawn mower (10) includes a driving source mounting portion (12) formed in a traveling frame (11), a driving source (13) mounted in the driving source mounting portion, and a lawn mowing unit (14) attached to the driving source. The lawn mowing unit is positioned below the traveling frame. A lower end (12b) of the driving source mounting portion and a lower end of the driving source are exposed from a bottom surface (17a) of the traveling frame. This bottom surface includes a frame-side seal surface (51) surrounding the lower end of the driving source mounting portion, and a lawn mowing unit peripheral surface (56) surrounding the frame-side seal surface. A waterproof member (70) is in tight contact with the frame-side seal surface, and waterproofs a portion between the bottom surface and driving source. When the lawn mower is viewed from below, the lawn mowing unit peripheral surface is formed over a range (Ar) from an outer circumferential edge (51b) of the frame-side seal surface to an outer circumferential edge (14a) of the lawn mowing unit. An inner circumferential edge (56a) of the lawn mowing unit peripheral surface is positioned higher than the outer circumferential edge of the frame-side seal surface. A boundary (57) between the frame-side seal surface and lawn mowing unit peripheral surface is formed into the shape of a step.