Power Tool Balancer Asymmetry for Vibration Reduction
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Solution Overview
Problem
Existing power tools experience increased vibration during workpiece processing due to resistance between the tool accessory and the workpiece, despite the use of balancers to reduce vibration caused by centrifugal forces.
Innovation Solution
A power tool design that incorporates a balancer with an asymmetrical shape and a projection to increase its weight, positioned to generate a centrifugal force that cancels the resistance between the tool accessory and the workpiece, with the balancer's center of gravity inclined relative to the rotation axis, enhancing vibration reduction without increasing the balancer's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a balancer is provided to reduce vibration caused by centrifugal force, then vibration from eccentric rotation is reduced, but vibration increases when the tool accessory contacts the workpiece due to resistance
Solution Approach 1:
The balancer is designed with an asymmetric mass distribution where the center of gravity is deliberately positioned not on the radial line passing through the eccentric axis, but at a specific angular position (inclination angle α) relative to it. This asymmetric configuration allows the balancer to generate a centrifugal force component that counteracts the resistance force during oscillation, rather than merely balancing the static centrifugal force.
Solution Approach 2:
The invention changes the positional parameter of the balancer's center of gravity from the conventional radial alignment to an inclined position at angle α. This parameter change transforms the balancer's function from simple centrifugal force balancing to active resistance compensation, where the centrifugal force generated by the inclined center of gravity creates a counteracting component during the oscillation cycle.
2Stability of the object's composition
If the balancer's center of gravity is positioned on the radial line through the eccentric axis, then centrifugal force balance is achieved, but the balancer cannot counteract resistance forces during workpiece contact
Solution Approach 1:
The balancer employs asymmetric mass distribution with the center of gravity positioned at an inclination angle α relative to the radial line through the eccentric axis. This asymmetry enables the balancer to generate a centrifugal force with a counteracting component that actively compensates for resistance forces during workpiece contact, improving processing stability.
Solution Approach 2:
The balancer is configured to generate a centrifugal force that preliminarily counteracts the resistance force before it fully impacts the system. By positioning the center of gravity at angle α, the balancer creates a proactive counteracting force that reduces the harmful effects of resistance during tool accessory contact with the workpiece.
3Stability of the object's composition
If the balancer size is increased to enhance vibration reduction, then centrifugal force balance improves, but the device complexity and size increase
Solution Approach 1:
Rather than increasing the balancer's size or mass, the invention achieves enhanced vibration reduction by changing the angular position parameter of the center of gravity. This parameter change (inclination angle α) allows the existing balancer mass to generate an optimized centrifugal force that counteracts resistance forces, avoiding the need for a larger or more complex balancer structure.
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 solution effectively inhibits vibration in power tools by aligning the balancer's centrifugal force with the resistance force at the point of contact, improving processing stability and reducing tool vibration.
Implementation Method 1
a centrifugal force is generated by rotation of the balancer in such a direction that the centrifugal force serves to cancel resistance generated by contact between the oscillating tool accessory and the workpiece
Data Source
AI summary
A power tool has a motor having a rotary shaft, an eccentric shaft configured to be rotated around a rotation center axis of the rotary shaft, and a balancer configured to rotate with the rotary shaft. When viewed along the rotation center axis, (1) a first imaginary line passes the rotation center axis and an eccentric axis, (2) an imaginary perpendicular line crosses perpendicularly to the first imaginary line and passes the rotation center axis, (3) a center of gravity of the balancer is located in a region on a side opposite to the eccentric axis across the imaginary perpendicular line; and (4) a second imaginary line passes the rotation center axis and the center of gravity of the balancer and (5) the second imaginary is inclined at an inclination angle larger than 0° and smaller than 90° in a direction opposite to a rotating direction of the rotary shaft.