Corrugated Stator Coil Forming via Segmented Wire Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for manufacturing stator coils using large square-shaped wires face challenges such as increased tensile and compression stresses on insulation films, high manufacturing costs due to the need for multiple die units, and reduced withstand voltage at boundary corners, making it difficult to produce coils with varying sizes efficiently.
Innovation Solution
A method involving a coil forming stage where a conductive wire is bent into a corrugated shape with alternating boundary corners, reducing stress on insulation films and allowing for adjustable coil end portions, using a tool set system that applies bending forces and forms corners one by one, simplifying the bending process and reducing mechanical impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If large square-shaped wires are bent using conventional die units to form stator coils, then the slot occupying ratio can be increased, but tensile stress and compression stress on the insulation film are inevitably increased
Solution Approach 1:
The bending process is divided into multiple stages with intermediate annealing steps. The wire is bent in segments rather than in a single operation, allowing stress to be distributed and managed through controlled intermediate states.
Solution Approach 2:
Annealing is performed as a preliminary action before bending to soften the wire and reduce its resistance to deformation. This preliminary heat treatment prepares the material to undergo bending with reduced stress concentration.
2Adaptability or versatility
If multiple die units with different sizes are used to form coil end portions of various lengths, then coils with different sizes can be manufactured, but manufacturing cost is considerably increased
Solution Approach 1:
A single die unit is designed to perform multiple functions by adjusting its position and the bending radius. The same die can create coil end portions of different lengths and configurations through controlled variation in operating parameters rather than requiring separate dedicated dies.
Solution Approach 2:
The bending process is made dynamic by allowing adjustment of the die position and bending radius during operation. This enables a single static die unit to produce variable coil geometries, replacing the need for multiple fixed-size die units.
3Shape
If wires are bent at right angles to form boundary corners between slot accommodated portions and coil end portions, then the coil structure is defined, but the insulation film is difficult to protect from damage
Solution Approach 1:
Annealing is applied beforehand to the wire before bending operations to increase its ductility and reduce the risk of insulation film damage during corner formation. This protective pre-treatment cushions the material against stress-induced damage.
Solution Approach 2:
The physical state of the wire is changed through temperature control (annealing) to alter its mechanical properties. By heating the wire to appropriate temperatures, its yield strength is reduced and ductility is increased, allowing corner formation without damaging the insulation film.
4Productivity
If conventional bending methods are used to form stator coils, then manufacturing process is established, but yield rate is reduced due to insulation film damage
Solution Approach 1:
Temperature is used as a controllable parameter to change the wire's mechanical properties during bending. By maintaining the wire at elevated temperatures during forming operations, the material becomes more forgiving to deformation, reducing defects and improving yield rate.
Solution Approach 2:
Annealing is performed as a preliminary step before bending to prepare the wire for deformation. This pre-treatment reduces the likelihood of insulation film damage during subsequent bending operations, thereby improving overall manufacturing yield.
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 method reduces stress on insulation films, prevents damage, lowers manufacturing costs, and allows for adjustable coil sizes, improving yield rates and productivity while maintaining the integrity of the insulation film.
Implementation Method 1
a wire bending tool set (103) for bending the wire (30) at the bending point (S703)
Implementation Method 2
the force applying tool set (102) is moved relative to the wire bending tool set (103) to apply a bending force onto the wire (30) at the force applying point
Data Source
AI summary
A first tool set holds a wire covered with an insulation film at a bending point of the wire to protrude the wire from the first tool set. A second tool set holds the protruded portion of the wire. The second tool set is rotated about the first tool set to bend the wire along a wall of the first tool set and to form a boundary corner in the wire at the same radius of curvature as the wall. The wire is released from the second tool set and is moved to place the first tool set at another bending point while protruding from the first tool set. The second tool set is placed at the protruded portion of the wire. When the wire is bent at a predetermined number of bending points and is rounded, a stator coil formed in a corrugated shape is manufactured.