Lawn Mower Blade Disk Rigidity and Vibration Control
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Solution Overview
Problem
Existing lawn mowers with rotating blade disks experience vibrations due to external forces during grass cutting, leading to unwanted operating noise, which is difficult to minimize without increasing costs through large-scale sound deadening devices.
Innovation Solution
The lawn mower incorporates a blade disk with a circumferential high-rigidity section and radial rigid sections, formed in a concave-convex configuration, to increase rigidity and minimize vibrations, and the blade mounting sections are located near the outer edge of the disk to effectively bear external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large-scale sound deadening device is provided on the lawn mower, then operating sound can be reduced, but the cost of the lawn mower increases significantly
Solution Approach 1:
The blade disk features localized high-rigidity sections with concave-convex configurations positioned between blade mounting sections. These localized structural modifications increase rigidity specifically where needed to reduce vibrations and operating sound, rather than requiring comprehensive sound deadening across the entire lawn mower. This resolves the contradiction by achieving noise reduction through targeted structural reinforcement instead of expensive large-scale sound deadening devices.
2Productivity
If the blade disk rotates at high speed to cut grass, then grass cutting efficiency is improved, but vibrations and operating sound increase due to external forces transmitted to the blade disk
Solution Approach 1:
The blade disk incorporates circumferential high-rigidity sections with concave-convex configurations that create curved, three-dimensional structural features. These curved reinforcements increase the disk's resistance to vibrations caused by high-speed rotation and external forces during grass cutting, allowing efficient operation without excessive noise. The curvature provides structural strength that flat surfaces cannot achieve, resolving the contradiction between productivity and noise control.
3Strength
If the blade mounting sections are located near the outer circumferential edge of the blade disk, then external force from cutter blades can be sufficiently borne, but the blade disk may experience waving phenomenon in the axial direction
Solution Approach 1:
The blade disk is segmented into distinct functional zones: blade mounting sections positioned near the outer circumferential edge for strength, and circumferential high-rigidity sections with concave-convex configurations positioned between the mounting sections to prevent waving. This segmentation allows each zone to perform its specific function - the mounting sections bear external forces while the high-rigidity sections maintain axial stability, resolving the contradiction between strength and stability.
Data Source
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AI summary
A lawn mower includes: a blade disk (20) rotatable about a rotation shaft (16a) extending in an up-down direction; and a plurality of cutter blades (71) mounted on the blade disk. The blade disk (20) includes a plurality of blade mounting sections (31) having corresponding ones of the cutter blades (71) mounted thereon, and a circumferential high-rigidity section (24) for increasing rigidity of the blade disk between the blade mounting sections (31). The blade mounting sections (31) are located on, and spaced from each other along, an imaginary reference circle (Cs) concentric with a rotation center of the blade disk, and the circumferential high-rigidity section (24) is located in such a manner as to interconnect the plurality of blade mounting sections along the reference circle, the circumferential high-rigidity section (24) being formed in a generally concave-convex configuration by being depressed and protruded in a facewise direction of the blade disk.