Utility Vehicle Blade Disk Rigidity and Vibration Control
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Solution Overview
Problem
Utility vehicles with increased rotating radius of the lawn mower blade disk experience louder mowing noise due to blade disk vibration, which is not effectively addressed by existing technologies.
Innovation Solution
A utility vehicle design featuring a circular blade disk with multiple blades attached at equally spaced positions, where a second disk is fixed to the center of the blade disk, enhancing its rigidity and reducing vibration and noise by being spaced apart and abutting on protrusions, thereby minimizing mowing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the rotating radius of the blade disk is increased to expand mowing width, then the mowing width is improved, but the blade disk vibration increases causing louder mowing noise
Solution Approach 1:
The blade disk is segmented into multiple independent blades attached at equally spaced positions around the circumference, rather than using a single large blade. This segmentation reduces the overall vibration amplitude of the rotating assembly, thereby reducing mowing noise while maintaining the expanded mowing width provided by the larger rotating radius.
Solution Approach 2:
The blades are positioned at equally spaced intervals around the circumference of the blade disk, creating a symmetric distribution pattern. This local arrangement ensures that vibration forces are balanced and cancel each other out, reducing net vibration and noise while allowing the blade disk to maintain a larger radius for wider mowing coverage.
2Area of moving object
If multiple blades are attached to the circumference of the blade disk, then the mowing width is expanded, but the blade disk rigidity decreases leading to increased vibration
Solution Approach 1:
The blade disk structure is segmented into multiple discrete blades rather than a solid continuous structure. This segmentation allows each blade to be independently optimized for strength-to-weight ratio, maintaining overall rigidity while reducing mass and vibration.
Solution Approach 2:
The blades are positioned at equally spaced asymmetric intervals around the circumference, creating a balanced distribution that enhances overall structural stability. This symmetric arrangement of identical elements creates rotational balance that maintains rigidity during rotation while allowing the expanded mowing width.
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 configuration significantly reduces blade disk vibration and subsequent mowing noise, enhancing the vehicle's operational efficiency and user experience by minimizing noise levels even when the mowing width is expanded.
Implementation Method 1
the fixing of the single second disk at the center of the blade disk to be spaced apart therefrom enhances rigidity of the blade disk and thereby reduces vibration of the blade disk
Data Source
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AI summary
In a utility vehicle, equipped with a lawnmower work unit (20) having a circular single blade disk (20a) rotatable around a rotating shaft connected to an output shaft of a work motor (prime mover) mounted on a chassis, and multiple (three) blades attached to circumference of the blade disk 20a at equally spaced apart positions, a single second disk (80) is fixed to middle of the surface of the blade disk (20a) of the lawnmower work unit (20) at positions that are spaced apart from each other.