Oscillating Work Tool Counterweight for Output Shaft Vibration
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Solution Overview
Problem
Vibration caused by the rotation of an output shaft connected to an eccentric shaft in power tools, leading to uneven force on the bearing and potential instability in the tool body.
Innovation Solution
A work tool design featuring a balancer connected to the output shaft, which counteracts the centrifugal force of the eccentric shaft, reducing the radial force on the bearing and minimizing vibration through a crank mechanism and strategically positioned weights that move in opposite phases to cancel out centrifugal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an eccentric shaft is connected to the output shaft to drive the tool accessory, then the tool accessory can be driven effectively, but vibration is caused in the work tool due to uneven force on the bearing
Solution Approach 1:
A balancer weight is connected to the output shaft at a position opposite to the eccentric shaft. The balancer weight generates centrifugal force in the opposite direction to counteract the centrifugal force of the eccentric shaft, thereby reducing the radial force on the bearing and suppressing vibration in the work tool.
Solution Approach 2:
The solution addresses the vibration problem by introducing a new spatial dimension - placing the balancer weight at a specific angular position (opposite side) and axial position (closer to the other end than the bearing member) relative to the eccentric shaft. This spatial arrangement allows the centrifugal forces to counterbalance each other effectively.
2Power
If the eccentric shaft is positioned closer to one end of the output shaft than the bearing member, then the tool accessory can be driven with sufficient torque, but the output shaft precesses around the bearing due to radial force
Solution Approach 1:
The balancer weight acts as a counterweight that offsets the radial force generated by the eccentric shaft's centrifugal force. By positioning the balancer weight opposite to the eccentric shaft and closer to the other end of the output shaft than the bearing member, the system achieves force balance that prevents output shaft precession while maintaining torque transmission capability.
3Object-affected harmful factors
If the balancer weight is positioned opposite to the eccentric shaft, then vibration is suppressed through centrifugal force counteraction, but the device complexity increases
Solution Approach 1:
The balancer weight is integrated with the output shaft assembly, forming a unified rotating component. This merging approach allows the balancer to perform vibration suppression functionality without requiring separate mounting structures or additional complex mechanisms, thereby minimizing the increase in device complexity.
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 balancer effectively suppresses vibration in the work tool, enhancing usability and durability by ensuring even force distribution on the bearing, thereby stabilizing the tool during operation.
Implementation Method 1
when the eccentric shaft is driven around the axial center of the output shaft of the motor, centrifugal force acts on the eccentric shaft
Implementation Method 2
By this centrifugal force, radial force acts on the front end of the output shaft of the motor. As a result, the output shaft which is supported in a cantilever form by a bearing precesses around the bearing. Therefore, during rotation of the output shaft, uneven force acts on the bearing. Thus, vibration may be caused in the power tool body via the bearing.
Data Source
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AI summary
[Problem] To provide an improvement technique for minimizing vibration occurring due to rotation of an output shaft of a motor to which an eccentric shaft is coupled. [Solution] This electric vibration tool (100) has: an electric motor (110) provided with an output shaft (111); an eccentric shaft (112) connected to one end of the output shaft (111); and a weight (170) connected to the other end of the output shaft (111). A blade (10) which functions as a distal tool is driven to rotate in reciprocating fashion about a spindle (115) due to reciprocating motion of the eccentric shaft (112) in relation to the lateral direction of the electric vibration tool (100). The output shaft (111) is then stably rotated by driving the weight (170) so as to offset the inertial force of the eccentric shaft (112).