Hybrid Power Control Unit Mounting Vibration Isolation
Solution Overview
Problem
In hybrid vehicle driving systems, mounting the power control unit directly on the case increases vibration, leading to potential connector failures and noise transmission to the passenger compartment, and poses challenges in disposing the power control unit relative to the engine's exhaust pipe, which is a heat source.
Innovation Solution
The power control unit is mounted on a case that accommodates a generator and a motor, with the generator and motor disposed side by side on the same axis, using connectors on the bottom surface of the power control unit to connect directly with case-side connectors, and the case is fixed to a vehicle framework member via a mount member, with fixing points strategically located near the connectors to reduce vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the power control unit is mounted directly on the case, then the vehicle body weight and cost are reduced and noise generation is suppressed, but the position of the center of gravity becomes high, increasing vibration and causing connector contact failures
Solution Approach 1:
The power control unit is divided into a upper housing and a lower housing that can be separated. The lower housing with connectors can be mounted on the case directly, while the upper housing containing heavy components is positioned separately to maintain lower center of gravity, thus preventing connector contact failures while still achieving weight reduction
Solution Approach 2:
The mounting structure transitions from a solid block mounting to a segmented housing structure where the lower housing is mounted on the case while the upper housing extends vertically. This dimensional separation allows the connectors to be positioned low on the case for stability while the overall unit maintains reduced weight through the segmented design
2Device complexity
If the power control unit is mounted directly on the case, then the mounting frame and three-phase cable are eliminated, but vibration increases leading to noise transmission to the passenger compartment
Solution Approach 1:
A vibration damping member is introduced as an intermediary between the lower housing and the case. This mediator absorbs and reduces vibrations generated by the power control unit, preventing noise transmission to the passenger compartment while maintaining the simplified direct mounting structure
Solution Approach 2:
The vibration damping member changes the vibration characteristics by introducing materials with different damping properties. This parameter change in the mounting interface reduces the transmission of vibration and noise to the case and passenger compartment while maintaining structural simplicity
3Ease of manufacture
If the power control unit is mounted directly on the case, then cost is reduced, but the disposal relative to the exhaust pipe heat source becomes problematic
Solution Approach 1:
The power control unit is segmented into upper and lower housings, allowing the lower housing with connectors to be mounted on the case away from the exhaust pipe, while the upper housing can be positioned or oriented to minimize heat exposure. This segmentation enables thermal management while maintaining cost-effective direct mounting
Solution Approach 2:
The housing structure is designed to extend in the vertical dimension, allowing the connectors to be positioned low on the case away from the exhaust pipe heat source. This dimensional arrangement enables thermal separation while maintaining the simplified mounting structure and low manufacturing cost
Data Source
AI summary
A hybrid vehicle driving system includes: a generator; a motor; a case which accommodates the generator and the motor; and a power control unit for controlling the generator and the motor, the generator and the motor being disposed side by side on a same axis within the case. The power control unit is mounted on the case by connecting a unit-side generator connector and a unit-side motor connector which are provided on a bottom surface of the power control unit with a case-side generator connector and a case-side motor connector which are disposed on the case, directly and respectively. The case is fixed to a vehicle framework member via a mount member, and a fixing point where the case and the mount member are fixed together is disposed near the case-side generator connector and the case-side motor connector.