Stepped Planetary Carrier Support With Single Bearing End Play Control
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Solution Overview
Problem
Existing single speed stepped planetary electrified transmissions with coaxial drive axles require two carrier support bearings to manage axial end play, which increases cost and size, while also potentially leading to noise, vibration, and bearing wear issues.
Innovation Solution
A coaxial electrified drive axle design that utilizes a single carrier support bearing to manage axial end play, eliminating the need for an inboard carrier support bearing and reducing the axial size of the transmission, while maintaining minimal noise, vibration, and bearing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two carrier support bearings are used to manage axial end play, then axial end play is controlled and bearing reliability is improved, but device cost and axial size increase
Solution Approach 1:
The patent removes the inboard carrier support bearing from the traditional two-bearing configuration, extracting only the essential outboard carrier support bearing. This elimination reduces device cost and complexity while the remaining bearing is designed to handle both radial and axial loads through specific geometric features (conical surface, stepped configuration) that provide axial end play control without requiring a second bearing.
2Object-affected harmful factors
If two carrier support bearings are used to manage axial end play, then axial end play is controlled and noise vibration is reduced, but device axial size increases
Solution Approach 1:
The patent combines multiple functions into the single outboard carrier support bearing: it supports radial loads, controls axial end play, and provides noise and vibration damping. The conical surface geometry and stepped configuration enable this bearing to perform the roles that traditionally required two separate bearings, thereby reducing axial size while maintaining noise and vibration performance.
3Device complexity
If a single carrier support bearing is used to eliminate cost and size, then device cost and axial size are reduced, but axial end play control and bearing wear become challenging
Solution Approach 1:
The patent changes the geometric parameters of the single carrier support bearing, specifically incorporating a conical surface with a defined angle and a stepped configuration. These parameter changes enable the bearing to maintain proper clearance control and load distribution, preventing excessive wear while using only one bearing. The specific geometry optimizes the bearing's ability to handle combined radial and axial loads.
4Length of moving object
If a single carrier support bearing is used to reduce axial size, then device axial size is reduced, but axial end play control and noise vibration become challenging
Solution Approach 1:
The patent optimizes the geometric parameters of the single carrier support bearing, including the conical surface angle and stepped dimensions, to ensure proper axial end play control. These parameter adjustments enable the bearing to maintain minimal clearance that reduces noise and vibration while keeping the overall axial size compact. The precise geometric configuration allows the bearing to function effectively as a single-component solution.
Data Source
AI summary
A coaxial electrified drive axle is provided for a vehicle. The coaxial electrified drive axle has an electric motor connected to a gear box housing containing a stepped planetary gear set operatively coupling a drive shaft of the electric motor to a linkshaft and an output shaft through a differential assembly. The differential assembly is contained within a carrier which also supports the planet gears through planet pins. The carrier is supported by a single carrier support bearing. The drive shaft, the linkshaft, and the output shaft are coaxial and share a common axis of rotation.