Power Tool Motor Stator Terminal Layout for Compact High Output

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Solution Overview

Problem

Existing motors in compact power tools face challenges in reducing their radial and axial dimensions while maintaining strong power output, due to the connection relationship between the input and output ends of the winding and external power control wires, making them less adaptable to small spaces.

Innovation Solution

The motor design incorporates connection terminals on the stator core, positioned on the side surface, which reduces the axial dimension and enhances adaptability by optimizing the arrangement of the terminal assembly and stator laminations, allowing for adjustable dimensions based on power output requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor uses traditional winding connection structures with external power control wires, then the connection reliability is improved, but the radial and axial dimensions of the motor increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmotor dimensions
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the terminal assembly with the stator core by integrating connection terminals directly into the stator laminations. The input and output ends of the winding are connected to these integrated terminals through the access slot, eliminating the need for separate external connection structures and reducing overall motor dimensions while maintaining connection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes the axial dimension of the stator core by forming connection terminals that extend axially from the stator laminations. The access slot is configured to receive terminal assemblies in the axial direction, allowing compact wire connections without increasing radial dimensions, thus achieving compactness in one dimension while maintaining connection functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the motor dimensions are reduced to fit compact power tools, then the adaptability to small spaces is improved, but the power output capability deteriorates

Engineering Contradiction:
Improveadaptability to small spacesVSAvoidpower output
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The patent segments the stator core into multiple laminations with different functional regions. First-type laminations provide connection arms and access slots for terminal connections, while second-type laminations provide winding receiving slots. This segmentation allows optimized space utilization and maintains electromagnetic performance in a compact configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables adjustable motor dimensions by varying the number of stator laminations stacked along the axial direction. This parameter change allows the motor to be customized for different power output requirements while maintaining the compact integrated terminal structure, thus adapting to different space constraints and power needs.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the terminal assembly is mechanically fixed to the stator frame, then the structural stability is improved, but the device complexity increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the terminal assembly with the stator core structure by integrating connection terminals directly into the stator laminations. The terminal assembly becomes an inherent part of the stator rather than a separate mechanically fixed component, reducing assembly complexity while maintaining structural stability through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

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 design results in a more compact and adaptable motor that effectively reduces the motor's dimensions, improving its suitability for use in power tools with limited space while maintaining high power output stability.

Implementation Method 1

an outer stator assembly comprising a stator core, first and second end plates made of insulating material and a winding wound onto the stator core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The motor drives a transmission assembly or an output assembly by outputting a torque

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP4012890B1Electric motor for an electric tool
Publication Date: 2025.01.08 NANJING CHERVON IND
  • EP4012890B1 patent drawingFigure 1
  • EP4012890B1 patent drawingFigure 2
  • EP4012890B1 patent drawingFigure 3

AI summary

Provided are a motor and a power tool, which belong to the technical field of power tools. The motor includes a stator assembly, a rotor assembly, and a terminal assembly. The stator assembly includes a stator core and a winding wound onto the stator core, where the winding includes an input end and an output end. The rotor assembly includes a rotor shaft extending along a direction of a first straight line. The terminal assembly is configured to connect or fix the input end and the output end. The stator core includes first-type laminations, where each of the first-type laminations is provided with connection arms and a special-shaped portion, special-shaped portions are configured to: when the first-type laminations are stacked along a direction parallel to the first straight line, form an access slot which is configured to connect the terminal assembly, and the access slot is disposed on an outer sidewall of the stator core. In the motor, a housing of the motor is fixed along a circumferential direction of the rotor shaft, thereby avoiding relative movement between the stator assembly and the housing of the motor along a direction of the rotor shaft during operation and improving operation stability of the motor.