Strain Wave Gear Built-in Motor Heat Dissipation
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Solution Overview
Problem
In strain wave gearing with a built-in motor, overheating occurs due to the motor heat being confined and not efficiently discharged, potentially causing adverse effects on structural components.
Innovation Solution
A heat-insulating spacing is introduced between the wave gear mechanism and the motor, with a cooling medium circuit that includes a shaft-side and end-face cooling medium circuit, allowing for efficient heat dissipation through the motor bracket, and the use of a high-thermal-conductivity resin for the stator coil to enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor is built into the strain wave reduction gearing, then the device size is reduced and integration is improved, but motor heat is confined and causes overheating of structural components
Solution Approach 1:
The patent extracts the heat dissipation function from the integrated motor-gearing structure by introducing a cooling medium circuit that penetrates through the motor bracket and stator coil. This allows heat to be taken out from the confined internal space and dissipated externally, resolving the overheating problem while maintaining the compact integrated design.
Solution Approach 2:
The patent introduces a cooling medium (water or air) as an intermediary substance to transfer heat from the motor interior to the exterior. The cooling medium flows through channels in the motor bracket and stator coil, acting as a thermal mediator that enables heat dissipation without compromising the integrated structure.
2Device complexity
If the wave generator is directly fixed to the motor rotor, then transmission members are eliminated and the structure is simplified, but heat transfer from motor to wave gear mechanism increases
Solution Approach 1:
The patent introduces a heat-insulating spacing as an intermediary thermal barrier between the motor rotor and wave generator. This spacing maintains the direct mechanical connection for rotation transmission while preventing thermal conduction from the hot motor to the wave gear mechanism, thus preserving structural simplicity while addressing heat transfer.
Solution Approach 2:
The patent segments the thermal path from the mechanical connection path. The heat-insulating spacing creates a thermal discontinuity while maintaining mechanical continuity, allowing the system to benefit from both direct coupling (simplicity) and thermal isolation (heat prevention).
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
Prevents overheating of the sliding and teeth-meshing portions, effectively minimizes heat transfer, and allows for efficient discharge of motor heat to the exterior, thereby preventing overheating and maintaining the structural integrity and efficiency of the strain wave gearing.
Implementation Method 1
a heat-insulating spacing disposed between the wave gear mechanism and the motor
Implementation Method 2
a cooling medium circuit that includes a shaft-side cooling medium circuit formed in the bracket shaft portion and an end-face cooling medium circuit formed along an outer surface of the bracket end plate portion
Implementation Method 3
allowing for efficient heat dissipation through the motor bracket
Implementation Method 4
the use of a high-thermal-conductivity resin for the stator coil to enhance heat dissipation
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A strain wave gearing with a built-in motor is provided with a motor, a wave gear mechanism enclosing the motor coaxially, and a heat-insulation spacing formed therebetween. The wave gear mechanism has a wave generator attached to the motor rotor so as to rotate integrally with the motor rotor. A wave generator plug of the wave generator is fixed to a rotor magnet back yoke of the motor rotor so as to enclose the rotor magnet back yoke. The spacing is formed in a contact surface portion between the rotor magnet back yoke and the wave generator back yoke, whereby heat transfer from the motor to the wave gear mechanism is suppressed.