Angle Grinder Motor Commutator Centrifugal Stability
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Solution Overview
Problem
High-speed rotating motors in angle grinders face challenges with commutator stability due to centrifugal forces, leading to positional changes and disengagement of commutator segments, which affects the motor's performance and longevity.
Innovation Solution
The design incorporates a commutator with a bushing, insulating member, and reinforcing rings, where the bonding and contact portions are strategically arranged with specific length differences and orientations to enhance bonding forces and prevent radial displacement, ensuring stable operation at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor operates at high rotating speed to increase power output, then the productivity and power of the angle grinder are improved, but the commutator segments experience huge centrifugal force causing positional bounce and disengagement from the base portion
Solution Approach 1:
The commutator is divided into multiple commutator segments that are sequentially distributed around the bushing. Each segment is independently bonded to the insulating member, allowing for better stress distribution and reduced radial displacement under centrifugal force during high-speed operation
Solution Approach 2:
The insulating member is pre-configured with bonding portions and connecting portions that strategically bond the commutator segments to the bushing before operation. This preliminary bonding structure prevents radial displacement and positional bounce before centrifugal forces act on the rotating commutator
2Reliability
If the commutator segments are bonded more strongly to prevent disengagement, then the reliability is improved, but the device complexity increases due to additional insulating members and bonding structures
Solution Approach 1:
The insulating member integrates multiple functions into a single component: it provides electrical insulation between segments, mechanically bonds segments to the bushing through bonding portions, and connects segments via connecting portions. This merging reduces the number of separate components while maintaining structural integrity
Solution Approach 2:
The insulating member serves multiple purposes simultaneously: electrical insulation, mechanical bonding, structural connection, and positional alignment of commutator segments. This multi-functionality reduces overall device complexity while achieving reliable commutator stability
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
This configuration improves the bonding force between commutator segments, reduces positional bounce, and extends the motor's service life by maintaining stable operation at higher rotating speeds, enhancing the power tool's performance and efficiency.
Implementation Method 1
an insulating member configured to bond the bushing and the plurality of commutator segments so as to constitute a whole
Implementation Method 2
When the motor operates at the high rotating speed, the commutator needs to bear a huge centrifugal force generated when the motor rotates
Data Source
AI summary
An angle grinder includes a housing, an output shaft, and a motor. The motor includes a stator assembly, a rotor assembly including a motor shaft configured to rotate about a first axis, a commutator, and a carbon brush. The commutator includes a bushing, configured to connect the commutator to the motor shaft, a plurality of commutator segments, sequentially distributed in a circumferential direction around the first axis and arranged around the bushing, and an insulating member, configured to bond the bushing and the plurality of commutator segments so as to constitute a whole.