Recessed Axle Housing Layout for Serviceable Motor Replacement
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Solution Overview
Problem
Existing axle structures with integrated drive motor units face challenges in maintainability and serviceability due to poor placement of the rotary electric machine, leading to increased load on joint regions during vehicle movement.
Innovation Solution
The axle structure features a recessed portion in the axle housing for housing the drive motor unit, allowing for easy replacement and integral fastening with the housing, which aligns the centers of gravity and reduces load from road surface movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the drive motor unit is placed inside the axle housing, then the axle structure size is minimized, but serviceability deteriorates due to poor maintainability when replacing the drive motor unit
Solution Approach 1:
The invention divides the axle housing into multiple segments: a first axle housing containing the drive motor unit, and a second axle housing containing the transmission and differential gear. This segmentation allows the drive motor unit to be replaced independently by removing only the first axle housing, significantly improving serviceability while maintaining the compact integrated design.
2Ease of repair
If the rotary electric machine is placed at an offset position outside the axle housing, then serviceability is improved, but reliability deteriorates due to heavy load on the joint region during vertical movement
Solution Approach 1:
The invention positions the drive motor unit within the first axle housing such that its center of gravity aligns with the center of gravity of the axle housing. This equipotential positioning eliminates offset between centers of gravity, ensuring that vertical movement loads are evenly distributed and preventing heavy concentrated loads on any single joint region, thereby maintaining reliability.
3Device complexity
If the drive motor unit is integrated with transmission and differential gear in a single housing, then device complexity is reduced, but serviceability worsens due to difficulty in replacing individual components
Solution Approach 1:
The invention segments the integrated drive motor unit assembly into two serviceable modules: the first axle housing containing the drive motor unit and the second axle housing containing the transmission and differential gear. This allows the drive motor unit to be replaced independently without disturbing the transmission and differential gear, resolving the serviceability issue while maintaining the benefits of integration.
Data Source
AI summary
An axle structure is provided with an axle housing for internally passing an axle shaft having wheels connected to both left and right ends thereof, and a drive motor unit. The axle housing includes a large diameter housing center portion having a recessed portion which is recessed from an opening portion on a front surface side toward a rear surface side, and small diameter hollow shaft portions connected as a left and right pair to both sides of the housing center portion. The drive motor unit is fitted into the recessed portion and is bolted to the axle housing by means of tightening bolts.