18-Tooth Electric Motor Reducing Torque Ripple
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Solution Overview
Problem
Conventional electric motors with an even number of teeth experience increased torque ripple, leading to vibration and operating noise, and the mounting of connecting wires and winding wires is cumbersome and costly.
Innovation Solution
An electric motor design with 18 teeth and 2 pole pairs, where winding wires are split into series connections using first and second conductive wires, reducing torque ripple and improving workability by minimizing axial dimensions and enhancing space factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an even number of teeth is used in the armature core, then the motor structure is simpler and easier to manufacture, but torque ripple increases leading to vibration and operating noise
Solution Approach 1:
The patent changes the numerical parameter of teeth from an even number to an odd number (specifically 18 teeth). This parameter change fundamentally alters the magnetic flux distribution pattern, reducing torque ripple while maintaining manufacturing simplicity. The odd number of teeth creates a more uniform distribution of magnetic forces throughout the rotation cycle.
2Reliability
If connecting wires are mounted separately from winding wires, then electrical connections are more reliable, but the mounting process becomes cumbersome and costly
Solution Approach 1:
The patent merges the functions of connecting wires and winding wires into a single integrated wire structure. This single wire performs both functions: it connects commutator segments and forms the armature coil winding. This integration simplifies the manufacturing process by eliminating separate mounting steps while maintaining reliable electrical connections through the continuous wire structure.
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 design reduces torque ripple, operating noise, and facilitates easier mounting of wires, resulting in a more efficient and cost-effective electric motor with improved performance.
Implementation Method 1
a magnetic field is formed in the teeth of the armature core due to an electric current which flows through the coil
Implementation Method 2
the armature is rotated with the rotary shaft by a magnetic attractive force or repulsive force which is generated between the teeth and the permanent magnets
Data Source
AI summary
In an electric motor, magnets (4) have two pairs of poles, the number of teeth (9) is 18, and the number of segments (14) of a commutator is 18. Winding wires (12, 25) for forming an armature coil (7) are formed by a first conductive wire (110) or a second conductive wire (120). The winding wire (25) has a first coil winding wire (7A) and a second coil winding wire (7B). The coil winding wires are each wound around four teeth (9) adjacent to each other. An end (31) of the second coil winding wire is connected to a segment (14) adjacent to a segment arranged at a position which is point symmetric with respect to a segment to which an end (30) of the first coil winding wire is connected. According to the invention, in the electric motor capable of changing the rotational speed of the armature by switching application of an electric current among three brushes, vibration and operating noise can be reduced, and mounting of the connecting wires and the winding wires can be facilitated.