Final Drive Gear Axial Preload Spring
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Solution Overview
Problem
The two-stage planetary gear arrangement in final drive assemblies for machines, such as off-highway trucks, experiences axial and radial movements leading to tilting misalignment, which causes premature failure of gear teeth.
Innovation Solution
The final drive assembly incorporates a first and second stage gear assembly with a ring gear, a cover, and bearing assemblies, where spring members are used to bias the components towards a second bearing assembly, limiting movement along the longitudinal axis and preventing tilting misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a two-stage planetary gear arrangement is used in the final drive assembly, then torque transmission capability is improved, but axial and radial movements cause tilting misalignment between gears leading to premature failure
Solution Approach 1:
The patent employs dynamic adjustment mechanisms including spring-loaded thrust bearings and adjustable shims that allow the gear assembly to self-compensate for axial and radial movements during operation, maintaining proper alignment while transmitting torque through the two-stage planetary gear arrangement
Solution Approach 2:
The invention changes the mechanical parameters of the gear assembly by introducing preloaded thrust bearings and adjustable spacers that modify the axial position and tilt angle of gears, thereby preventing misalignment while preserving torque transmission capability
2Force
If resilient means are used to urge the third element into frictional engagement to provide torque reaction, then torque reaction is established, but axial and radial movements of gear set components are not prevented
Solution Approach 1:
The patent segments the torque reaction function from the alignment constraint function by using separate components: resilient means provide torque reaction while dedicated thrust bearings and adjustable shims handle axial and radial alignment constraints
Solution Approach 2:
The invention introduces intermediary components such as thrust bearings and adjustable spacers that mediate between the resilient torque reaction means and the gear elements, preventing direct transmission of axial and radial movements while maintaining torque reaction capability
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 reduces or prevents tilting misalignment, thereby reducing damage and increasing the operational life of the gear components by constraining movement and applying axial loads to maintain alignment.
Implementation Method 1
a spring member disposed between the first bearing assembly and the cover. The spring member is configured to bias the first bearing assembly, the first carrier and the second sun gear towards the second bearing assembly to limit a movement of each of the first stage gear assembly and the second stage gear assembly along the longitudinal axis
Data Source
AI summary
A final drive assembly for a machine includes an input shaft drivably coupled to a prime mover. The input shaft is coupled to and drives a first stage gear assembly. The first stage gear assembly further drives a second stage gear assembly. The first and second stage gear assemblies drive a ring gear which is coupled to a wheel of the machine. The first and second stage gear assemblies are disposed between a first bearing assembly and a second bearing assembly. A spring member preloads the first bearing assembly to limit an axial movement of the first and second stage gear assemblies.