In-wheel Motor Breather Mechanism for Pressure Equalization
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Solution Overview
Problem
In-wheel motor units for electric vehicles face challenges in maintaining complete liquid tightness due to pressure changes caused by temperature fluctuations, leading to moisture absorption issues.
Innovation Solution
The implementation of an in-wheel motor unit with a hollow axle, a rotatable motor housing, and a breather mechanism that allows air pressure inside the motor housing to be adjusted, ensuring communication with outdoor air through the axle and arm internal spaces, thereby maintaining liquid tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waterproof measures are taken in the motor housing to prevent water entry, then liquid tightness is improved, but pressure changes due to temperature fluctuations cause moisture absorption
Solution Approach 1:
A breather mechanism is introduced as an intermediary component between the motor housing interior and the external environment. This breather mechanism includes a breather hole and a breather cap that selectively allows pressure equalization while blocking moisture entry, thus mediating between the need for liquid tightness and pressure regulation
Solution Approach 2:
The breather mechanism creates a protected environment by allowing air exchange while preventing moisture contamination. The breather cap design ensures that the interior space maintains a relatively inert atmosphere resistant to moisture ingress despite pressure changes
2Object-affected harmful factors
If the motor housing is sealed to prevent water entry, then waterproofing is improved, but pressure changes from temperature fluctuations cause moisture absorption
Solution Approach 1:
The sealing system transitions from a static complete seal to a dynamic system with the breather mechanism. The breather mechanism dynamically adjusts to pressure changes by opening/closing the breather hole based on internal pressure conditions, allowing the system to adapt between sealed and vented states
Solution Approach 2:
The breather mechanism changes the operational parameters of the sealing system by introducing controlled permeability. The breather cap design allows pressure parameters to equalize with the external environment while maintaining protection against moisture, thus changing the sealing parameter from complete impermeability to selective permeability
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 solution effectively adjusts air pressure inside the motor housing, preventing moisture absorption and ensuring reliable operation despite temperature-induced pressure changes.
Implementation Method 1
the air pressure inside the motor housing can be adjusted... communicates with outdoor air by the breather mechanism through the axle internal space and the arm internal space
Data Source
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AI summary
An in-wheel motor unit includes an in-wheel motor (72) having a hollow axle (26) in which an axle internal space (28) allowing a first axle opening (30) to communicate with a second axle opening (32) is formed, a stator (74) fixed to the axle and a hollow motor housing (38) in which a motor internal space (64) to which the first axle opening of the axle opens is formed thereinside, a first seal (70) for securing liquid tightness of the motor internal space between the motor housing and the axle, a hollow arm (96) in which an arm internal space (114) to which the second axle opening opens is formed thereinside, to which the axle is fixed so as to be detachable, a second seal (112) for securing liquid tightness of the arm internal space between the arm and the axle, and a breather mechanism 116 (a first arm opening) opening to the arm internal space and communicating with outside air.