E-Bike Motor Unit Metallic Cup Cooling for Stator Heat Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric bicycle motor units face challenges in effectively dissipating heat generated during operation, which affects performance and efficiency.
Innovation Solution
The motor unit incorporates a metallic cup that is thermally inserted onto the stator to directly transfer heat away from the motor, reducing the use of resin and enhancing heat dissipation through direct contact with the open air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a motor case is resin-molded along with a stator by a molding technique, then the manufacturing process is simplified and the structure is integrated, but the heat dissipation capability is insufficient
Solution Approach 1:
The invention uses a composite structure where the stator is resin-molded for ease of manufacture, but a metallic cup (aluminum or other metal) is added around the stator to provide heat dissipation. This combines the advantages of resin molding (integration, ease of manufacture) with the thermal conductivity of metal materials, resolving the contradiction between manufacturing simplicity and heat dissipation performance.
2Stability of the object's composition
If more resin is used to house the motor components, then the structure is more complete and components are better protected, but the weight of the motor unit increases
Solution Approach 1:
The invention extracts the heat dissipation function from the resin motor case and assigns it to a separate metallic cup component. This allows the resin to be used only where structural protection is needed, while the metal cup provides both heat dissipation and additional structural support, reducing overall weight by eliminating excess resin material.
3Temperature
If a metallic cup is thermally inserted onto the stator, then heat dissipation is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The metallic cup is designed with a thermal insertion fit that allows it to be attached to the stator in a single operation. The cup is preliminarily sized to create an interference fit that, when heated, expands to accommodate the stator, then contracts upon cooling to secure the attachment. This preliminary design of the fit dimensions simplifies the manufacturing process by eliminating the need for complex fastening mechanisms.
4Temperature
If the metallic cup is in pressure contact with the stator, then heat transfer efficiency is improved, but the risk of damage to the stator increases
Solution Approach 1:
The invention carefully controls the pressure contact parameters between the metallic cup and stator by designing the thermal insertion fit with specific dimensional tolerances. The interference fit is calculated to generate sufficient contact pressure for effective heat transfer while remaining below the threshold that would damage the stator windings or core. This parameter optimization resolves the contradiction between heat transfer efficiency and structural integrity.
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 improves heat dissipation capabilities, reduces the overall weight of the motor unit, and minimizes temperature increases and vibrations, while maintaining insulation and reducing noise.
Implementation Method 1
a metallic cup (57) to house the stator (53) and the rotor (52). An inner peripheral surface (570) of the metallic cup (57) is in pressure contact with the stator (53). The heat generated from the stator (53) is transferred to the metallic cup (57)
Implementation Method 2
The heat generated from the stator (53) is transferred to the metallic cup (57) and radiated directly to the open air
Implementation Method 3
An inner peripheral surface (570) of the metallic cup (57) is in pressure contact with the stator (53). This design improves heat dissipation capabilities, reduces the overall weight of the motor unit, and minimizes temperature increases and vibrations
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Provided are a motor unit with improved heat dissipation capability for electric bicycles and an electric bicycle including such a motor unit. A motor unit (3) for use in electric bicycles includes a motor (5) and a unit case (4) to which the motor (5) is fitted. The motor (5) includes: a stator (53); a rotor (52) arranged to be surrounded with the stator (53); a rotary shaft (51) fixed to the rotor (52); and a metallic cup (57) to house the stator (53) and the rotor (52) at least partially. An inner peripheral surface (570) of the metallic cup (57) is in pressure contact with the stator (53).