EV Drive Unit Layout With Bottom-Fed PN Line for Compact Mounting
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Solution Overview
Problem
Conventional vehicle drive devices face challenges in enhancing mountability due to the increased size caused by the placement of power supply lines and ferrite cores, which hinder compact design and integration with other vehicle components.
Innovation Solution
The vehicle drive device incorporates a gearbox offset in the front-rear direction, with an inverter case positioned above the motor housings, and power lines connected from the lower surface to pass through a bulging space, allowing for a more compact design and improved integration with other vehicle components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the PN line is inserted from the upper surface or back surface of the inverter and fastened to the busbar inside the inverter, then the electrical connection is reliable, but the size of the inverter in the vehicle front-rear direction increases
Solution Approach 1:
The patent inverts the conventional connection approach by routing the PN line from the lower surface of the inverter case instead of the upper or back surface. The line passes through a through-hole in the lower surface, enters the inverter from below, and connects to the busbar. This inversion allows the connection to be made without increasing the front-rear dimension of the inverter, as the routing path is changed from top-to-bottom or back-to-front to bottom-to-top.
Solution Approach 2:
The patent changes the spatial dimension of the PN line routing by utilizing the vertical dimension (passing through the thickness of the inverter case from lower surface) rather than extending in the front-rear horizontal dimension. The line enters through a through-hole in the lower surface and routes upward inside the inverter, effectively using the depth dimension to accommodate the connection path.
2Object-affected harmful factors
If the ferrite core is made to largely protrude to the outside of the inverter, then the noise countermeasure effectiveness is improved, but the size of the entire device increases and vehicle mountability is deteriorated
Solution Approach 1:
The patent integrates the ferrite core within the inverter case structure rather than having it protrude externally. The core is positioned inside the inverter housing, nested within the overall device boundaries, which maintains the noise suppression function while avoiding external protrusion that would increase the device envelope dimensions.
Solution Approach 2:
The patent combines the ferrite core with the inverter case structure, integrating the noise countermeasure component into the main housing rather than treating it as a separate external element. This merging allows the core to be accommodated within the existing structural volume of the inverter case.
3Ease of manufacture
If the inverter is designed with conventional PN line routing, then the electrical connection is straightforward, but the vehicle mountability is reduced due to increased size
Solution Approach 1:
The patent inverts the conventional routing approach by connecting the PN line from the lower surface instead of the upper or back surface. This inverted routing method maintains manufacturing simplicity while enabling compact integration and improved vehicle mountability by eliminating the need for extended front-rear space.
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 configuration enhances vehicle mountability by reducing the overall size of the device, improving workability, and allowing for efficient use of space, while maintaining performance and avoiding interference with other structural elements.
Implementation Method 1
a pair of semiconductor modules converting direct current to alternating current and supplying the alternating current to the left and right motors
Implementation Method 2
a ferrite core, which is provided as a countermeasure against noise
Implementation Method 3
the gearbox amplifying torque of the left and right motors and transmitting the amplified torque to the left and right wheels
Data Source
AI summary
The disclosed vehicle drive device (10) includes: motor housings (11,12), a gearbox housing (13), an inverter case (14), and a PN line (9). The motor housings (11,12) form respective exteriors of a left motor (1) and a right motor (2) that drive left and right wheels of a vehicle with electric power of a battery. The gearbox housing (13) incorporates therein a gearbox (3) that amplifies torque of the left and right motors and that transmits the amplified torque to the left and right wheels, is sandwiched between the left and right motor housings (11,12), and is offset in a front-rear direction from the left and right motor housings (11,12). The inverter case (14) incorporates therein a pair of semiconductor modules (6,7) and is arranged above the left and right motor housings (11,12). The PN line (9) connects the battery to the semiconductor modules (6,7) from a lower surface side of the inverter case (14) so as to pass through a first space (41).