Brushless Motor Terminal Layout for Shorter Axial Length
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Solution Overview
Problem
Existing brushless motors face challenges in reducing size and improving layout flexibility due to the thick molded busbar overlapping the stator in the axial direction and the connector part protruding radially, limiting their compactness and adaptability.
Innovation Solution
The motor device features a stator with a cylindrical core and core protrusions that fit into corners of a polygonal motor case, along with connection terminals between the rotor and coils, allowing for a more compact design and improved layout flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molded busbar is used to connect coils, then electrical connection is achieved, but the axial length of the motor increases due to the thickness of the busbar overlapping the stator
Solution Approach 1:
The patent extracts the connection terminal from the traditional molded busbar structure and positions it in the radial direction between the rotor and stator. This removes the axial overlap issue while maintaining electrical connection functionality through a more space-efficient configuration.
Solution Approach 2:
The patent transitions the connection terminal arrangement from the axial dimension (traditional busbar overlapping stator) to the radial dimension (between rotor and stator). This dimensional change eliminates axial length increase while preserving electrical connectivity.
2Reliability
If a connector part is provided in the terminal holder and cover, then electrical connection is achieved, but the radial protrusion reduces layout flexibility with respect to fixing objects
Solution Approach 1:
The patent extracts the connection terminal from the protruding connector structure and repositions it flush with the motor case surface. This eliminates radial protrusion while maintaining electrical connection capability, thereby improving layout flexibility.
Solution Approach 2:
The patent employs an asymmetric arrangement where connection terminals are positioned at specific radial locations between rotor and stator, allowing optimized space utilization and eliminating uniform radial protrusion that limited mounting flexibility.
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 enables a further reduction in motor size and enhances its adaptability to fixing objects by optimizing the stator and rotor arrangement.
Implementation Method 1
a coil, wound on each of the plurality of teeth for each phase
Implementation Method 2
a magnet, provided on an outer peripheral part of the rotating shaft
Data Source
Figure 1
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AI summary
A cross-sectional shape of a motor case (21) along a radial direction of a rotor (40) is a square including corners (24a to 24d). The stator (30) includes: a core body (32); a core protrusion (33a to 33d), abutting against each of the corners (24a to 24d); teeth (34); and a coil (36), wound on each tooth (34) for each phase. The rotor (40) includes: a rotating shaft (41); and a ring magnet (43), provided on an outer peripheral part of the rotating shaft (41). In the radial direction of the rotor (40), between the rotor (40) and the corners (24a to 24c) and on line segments (L1 to L3) connecting a rotation center (C) of the rotor (40) and the corners (24a to 24c), connection terminals (Tu, Tv, Tw) of three phases are arranged that are respectively electrically connected to the coils (36) provided for each phase.