Electrified Vehicle Case Body Segmentation for NV Suppression
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Solution Overview
Problem
In electrified vehicles with an electromechanical integration unit, noise and vibration (NV) deteriorate due to overlapping frequency components between the engine's forced force and the resonance frequency of the electric motor, power transmission device, and power control device housed in the same case, leading to increased vibration and noise levels.
Innovation Solution
The electrified vehicle design includes a case with a housing connected to the engine block and a case body with a first wall part, where a plate part fixes the power control device, and a first fastening member connects to the first wall part, improving the rigidity of the connection parts and suppressing vibration by positioning them to face each other with the first wall part interposed, thus enhancing the rigidity and reducing bending of the case body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the power control device is housed together with the power transmission device in the same case as an electromechanical integration unit, then device integration is improved, but NV (noise and vibration) deteriorates due to overlapping frequency components between engine forced force and resonance frequency
Solution Approach 1:
The case is divided into a housing connected to the engine block and a case body housing the electromechanical integration unit. The connection parts are positioned to face each other with the first wall part interposed between them, creating a segmented structure that reduces vibration transmission while maintaining integration.
Solution Approach 2:
The first wall part acts as an intermediary element between the housing and the case body. By positioning connection parts to face each other with the first wall part interposed, it serves as a mediator that reduces the direct transmission of vibration and noise from the engine to the electromechanical integration unit.
2Stability of the object's composition
If the connection part between housing and case body is rigidly connected, then structural stability is improved, but vibration transmission from engine to electromechanical integration unit increases
Solution Approach 1:
The connection structure is segmented into the housing, the first wall part, and the case body as separate components. The connection parts are positioned to face each other with the first wall part interposed, creating a segmented connection that maintains structural stability while reducing vibration transmission through the intermediate wall structure.
3Object-affected harmful factors
If the case body is made more rigid to suppress bending, then vibration suppression is improved, but device complexity increases
Solution Approach 1:
Instead of making the entire case body more rigid, the structure is segmented into the housing and case body connected through positioned connection parts. The first wall part is configured to reduce bending, providing vibration suppression through the segmented structure rather than increasing overall rigidity, thereby avoiding excessive complexity.
Data Source
AI summary
The first fastening member, to which the engine-side end of the plate part that fixes a part of the power control device, is fastened is connected to the first wall part of the case body. In addition, the connection part between the housing to which the engine block is connected and the first wall part and the connection part between the first fastening member and the first wall part are located at positions facing each other with the first wall part interposed between the connection parts. Thus, the rigidity of the connection part between the housing and the case body is improved, bending of the case body starting from the connection part is suppressed, and vibration of the electromechanical integration unit is suppressed. Therefore, deterioration of NV in the electromechanical integration unit is able to be suppressed.