Differential Gear Side Gear Structure for Spacer-Free Shaft Positioning
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Solution Overview
Problem
Existing differential gears face challenges in positioning a pair of output shafts during vehicle assembly without using an axle spacer, which also obstructs lubricating oil flow.
Innovation Solution
A differential gear design that includes cylindrical connecting members with straight-spline protrusions for shaft coupling and helical-spline couplings generating frictional forces between side gears and a center washer to facilitate shaft positioning, while allowing differential rotation and maintaining lubricating oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an axle spacer is disposed between the first side gear and the second side gear to facilitate positioning of output shafts during assembly, then the ease of assembly is improved, but the lubricating oil flow in the differential case is obstructed
Solution Approach 1:
The invention removes the axle spacer component from the differential gear assembly. Instead of using a separate spacer component, the positioning function is integrated into the side gears themselves through the protruding wall portions that extend beyond the connecting members, eliminating the obstruction to lubricating oil flow while maintaining assembly ease
Solution Approach 2:
The invention merges the positioning function previously performed by the separate axle spacer into the side gear structure itself. The first and second wall portions of the side gears are designed to protrude radially inward beyond the connecting members, directly providing the positioning function that was previously separated into a distinct component
2Reliability
If the first and second side gears are pressed against washers by thrust forces from helical gear meshing to generate frictional forces for limited slip function, then the differential rotation limitation is improved, but the heat generation and wear increase
Solution Approach 1:
The invention introduces dynamic adjustment of the frictional force through the spring member that applies axial force to the center washer. This allows the differential limiting characteristic to adapt to varying operating conditions, reducing excessive heat generation and wear during normal operation while maintaining effective limitation when needed
Solution Approach 2:
The invention changes the frictional force parameter dynamically through the spring-loaded center washer mechanism. The spring force can be adjusted to optimize the balance between differential limitation effectiveness and heat/wear reduction, allowing parameter optimization based on operational requirements
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
Facilitates axial positioning of output shafts during assembly without an axle spacer, reduces heat and wear, and ensures efficient lubrication by maintaining oil flow, thus improving assembly efficiency and reducing component wear.
Implementation Method 1
a first cylindrical portion disposed around an outer periphery of the first connecting member and coupled to the first connecting member by helical splines; a first wall portion extending radially inward from one end on the center washer side of the first cylindrical portion
Implementation Method 2
the center washer generates a frictional force between the center washer and each of the first wall portion of the first side gear and the second wall portion of the second side gear by a thrust force generated by coupling by the helical splines
Data Source
AI summary
A differential gear includes a first connecting member with straight-spline protrusions on its inner periphery; a second connecting member with straight-spline protrusions on its inner periphery; a first side gear; and a second side gear. The first side gear includes a first cylindrical portion coupled to the first connecting member by helical splines, and a first wall portion extending radially inward. The second side gear includes a second cylindrical portion coupled to the second connecting member by helical splines, and a second wall portion extending radially inward. The first wall portion of the first side gear protrudes radially inward beyond the straight-spline protrusions of the first connecting member, and the second wall portion of the second side gear protrudes radially inward beyond the straight-spline protrusions of the second connecting member.