Intermediate Member Stator Fastening for Vehicle Driving Apparatus
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Solution Overview
Problem
Existing vehicle driving apparatuses with low radial and circumferential stator rigidity suffer from increased stator vibration-related noise issues, such as 6n-th and 12n-th order noise, due to poor vibration damping and resonance frequency shifts, leading to increased vibration transmission sensitivity.
Innovation Solution
A vehicle driving apparatus with a rotating machine, a motor case, and an intermediate member featuring a flat plate-shaped main body and an annular protrusion with stator fastening portions, where the stator is cantilever-supported by the intermediate member, which is fastened to a high rigidity portion of the motor case, maintaining circumferential rigidity while reducing radial rigidity to dampen stator vibrations effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the stator is supported in a cantilever manner by the protrusion of the intermediate member, then the rigidity of the stator in radial direction is reduced to dampen vibrations, but the rigidity of the stator in circumferential direction must be maintained to prevent noise increase
Solution Approach 1:
The intermediate member's annular protrusion creates a structural configuration where radial rigidity is reduced (through the protrusion geometry) to dampen radial vibrations, while circumferential rigidity is maintained (through the annular structure's inherent stiffness) to prevent increases in 6n-th and 12n-th order noise.
Solution Approach 2:
The intermediate member acts as a mediator between the stator and motor case, providing differential rigidity properties in different directions. It transmits circumferential forces with high rigidity while allowing radial vibration damping, thus resolving the contradiction between maintaining circumferential strength and reducing radial vibrations.
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 effectively reduces all types of motor noise caused by stator vibration by maintaining circumferential rigidity to prevent noise increase and shifting resonance frequencies, while damping radial vibrations, thus minimizing transmission to the motor case.
Implementation Method 1
damping radial vibrations, thus minimizing transmission to the motor case
Data Source
AI summary
A vehicle driving apparatus including: a rotating machine including a rotor and a stator; a motor case storing therein the rotating machine and fastened to a non-rotary member; and an intermediate member including (i) a main body having a flat plate shape and (ii) a protrusion which protrudes in a direction of an axis of the rotating machine from a surface of the main body on a side of the rotating machine and which has an annular shape surrounding the axis. The protrusion of the intermediate member includes a plurality of stator fastening portions through which the stator of the rotating machine is fastened to the intermediate member. The intermediate member is fastened to a high rigidity portion of the motor case that has a higher rigidity than the other portion of the motor case.