Vehicle Drive Unit Bearing Mounting for Vibration Isolation
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Solution Overview
Problem
The existing drive units of mobility devices experience vibrations that cause noise and potentially damage components, as these vibrations are transmitted to the casing and affect the operation of the main shaft, intermediate shaft, and differential.
Innovation Solution
A drive unit design where the first rolling bearing is mounted without clearance on the second shell using axial retention means such as circlips or screws, concentrating vibrations near the electric motor and preventing their transmission to the first shell, while a second rolling bearing with clearance on the first shell further isolates it from vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first rolling bearing is mounted with clearance on the second shell, then the assembly is easier and manufacturing is simpler, but vibrations are transmitted to the first shell causing noise and component deterioration
Solution Approach 1:
The patent introduces axial retention means (circlip or screw) as an intermediary element between the first rolling bearing and the second shell. This intermediary component enables secure mounting without clearance while simplifying the assembly process. The retention means acts as a mediator that transfers the mounting function from a complex interference fit to a simple snap-fit or screw-fixed configuration, thereby achieving both ease of manufacture and vibration isolation.
2Object-affected harmful factors
If the first rolling bearing is mounted without clearance on the second shell, then vibration transmission to the first shell is reduced, but the assembly and manufacturing become more complex
Solution Approach 1:
The axial retention means serves as a mediator that simplifies the assembly process while achieving the goal of mounting without clearance. The circlip or screw acts as an intermediate component that enables precise positioning and secure fixation of the bearing, eliminating the need for complex interference fits or specialized assembly equipment.
Solution Approach 2:
The patent segments the mounting function into two distinct parts: the bearing itself and the axial retention means. This segmentation allows the bearing to be mounted easily with clearance, while the retention means provides the without-clearance fixation. By dividing the mounting system into separate functional components, the patent achieves both ease of assembly and vibration isolation.
3Object-affected harmful factors
If axial retention means are used to mount the first rolling bearing without clearance, then vibrations are concentrated at the second shell near the electric motor, but the device complexity increases
Solution Approach 1:
The axial retention means acts as a simple intermediary component that achieves vibration concentration without requiring complex mechanisms. The circlip or screw provides a straightforward solution that adds minimal complexity while effectively isolating vibrations to the second shell. The retention means serves as a simple mediator that transfers vibrational energy locally without propagating it to the first shell.
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 design effectively reduces vibrations on the first shell, minimizing noise and protecting the casing components by isolating the vibrations at the second shell, thereby ensuring the proper operation of the main shaft, intermediate shaft, and differential.
Implementation Method 1
the first rolling bearing is mounted without clearance on the second shell by way of first axial retention means... concentrating the vibrations at the second shell, close to the electric motor
Implementation Method 2
a second rolling bearing with clearance on the first shell further isolates it from vibrations
Data Source
AI summary
A drive unit of a mobility device, including an electric machine, a casing including a first shell and a second shell, the second shell being situated between the electric machine and the first shell, and a main shaft which is housed in a space delimited by the first shell and the second shell and is able to be set in rotation by the electric machine. The main shaft is mounted on the second shell by way of a first rolling bearing. The first rolling bearing is mounted without clearance on the second shell by way of first axial retention means.